{ "spore": "profile", "id": "palladium", "spore_version": "0.2", "family": "precious-metals", "name": "Palladium", "abbreviation": "Pd", "role": "catalyst, electrical-contact and hydrogen-handling metal", "category": "metals", "type": "precious-metals", "summary": "Palladium is a dense, soft, silver-white platinum-group metal. Reference data list a density of 12.02 g/cm3 and a melting point of 1554.9 degC, and a supplier datasheet gives an annealed tensile strength of 280 MPa. Its most distinctive trait is that it soaks up hydrogen: at 25 degC and 1 bar the hydrogen-rich beta phase holds about 0.7 hydrogen atoms per palladium atom, and the lattice swells by more than 10% when it forms. The USGS lists its uses as catalytic converters, chemical and refinery catalysts, and electronics such as multilayer ceramic capacitors. A NASA-sponsored 1969 device used a palladium-silver alloy to strip dissolved hydrogen from fuel-cell water.\n", "best_for": "Catalysis and selective hydrogen passage (a 75% palladium-25% silver alloy dropped dissolved hydrogen from 60 psia to under 0.5 psia in a NASA-sponsored separator)", "weakest_at": "Hydrogen embrittlement: pure palladium membranes warp and fracture when the alpha-to-beta hydride transition expands the lattice by more than 10%, and supply is concentrated in two countries", "identity": { "formula": "Pd", "cas": "7440-05-3", "crystal_system": "face-centred cubic", "designations": [], "source": "pubchem-pd", "where": "Record \"Palladium\" (CID 23938), Names and Identifiers (molecular formula Pd; CAS 7440-05-3 in the ECHA registration link); face-centred cubic structure with a = 3.891 angstrom from the Goodfellow General Properties table" }, "tags": { "environments": [ "low-earth-orbit" ], "stresses": [], "applications": [ "electronics-and-chips", "propulsion-and-tanks", "cryogenic-fuel" ] }, "properties": [ { "benchmark": "density", "label": "Density of palladium metal", "value": 12.02, "bound": "exact", "unit": "g/cm3", "scope": "material", "conditions": { "form": "bulk metal, purity not stated", "temperature": "not stated for this entry" }, "method": "Handbook value listed in PubChem from the Hazardous Substances Data Bank, which cites Kirk-Othmer Encyclopedia of Chemical Technology, 4th ed., vol. 19, p. 350 (1996)", "status": "ground", "note": "Other sources agree. Goodfellow lists 12.02 g/cm3 at 20 degC, Deringer-Ney lists 12.02 g/cm3, and WebElements lists 12023 kg/m3 for the solid.", "source": "pubchem-pd", "where": "Chemical and Physical Properties > Experimental Properties > Density (first entry)", "source_detail": { "title": "PubChem compound record, Palladium (CID 23938)", "id": "CID 23938; CAS 7440-05-3", "url": "https://pubchem.ncbi.nlm.nih.gov/compound/Palladium", "year": 2026, "kind": "database", "license": "public domain (NCBI); cited handbooks are not reproduced" } }, { "benchmark": "melting_point", "label": "Melting point", "value": 1554.9, "bound": "exact", "unit": "degC", "scope": "material", "conditions": { "pressure": "not stated", "form": "pure metal" }, "method": "Handbook value listed in PubChem, citing Lide (ed.), CRC Handbook of Chemistry and Physics, 81st ed., 2000, p. 4-77", "status": "ground", "note": "PubChem also lists 1554.8 degC from another entry. Deringer-Ney gives a melting temperature of 1552 degC for its palladium and Goodfellow gives 1,554.9 degC (1,828.0 K).", "source": "pubchem-pd", "where": "Chemical and Physical Properties > Experimental Properties > Melting Point", "source_detail": { "title": "PubChem compound record, Palladium (CID 23938)", "id": "CID 23938; CAS 7440-05-3", "url": "https://pubchem.ncbi.nlm.nih.gov/compound/Palladium", "year": 2026, "kind": "database", "license": "public domain (NCBI); cited handbooks are not reproduced" } }, { "benchmark": "boiling_point", "label": "Boiling point", "value": 2963, "bound": "exact", "unit": "degC", "scope": "material", "conditions": { "pressure": "760 mm Hg (the second PubChem entry states this)" }, "method": "Handbook value listed in PubChem, citing Lide (ed.), CRC Handbook of Chemistry and Physics, 81st ed., 2000, p. 4-77", "status": "ground", "source": "pubchem-pd", "where": "Chemical and Physical Properties > Experimental Properties > Boiling Point", "source_detail": { "title": "PubChem compound record, Palladium (CID 23938)", "id": "CID 23938; CAS 7440-05-3", "url": "https://pubchem.ncbi.nlm.nih.gov/compound/Palladium", "year": 2026, "kind": "database", "license": "public domain (NCBI); cited handbooks are not reproduced" } }, { "benchmark": "thermal_conductivity", "label": "Thermal conductivity", "value": 72, "bound": "exact", "unit": "W/(m.K)", "scope": "material", "conditions": { "form": "pure metal", "temperature": "not stated on the page" }, "method": "Value listed in the WebElements physical-properties table", "status": "ground", "note": "Goodfellow lists 71.8 W/m.K and Deringer-Ney lists 70 W/m-K (40 Btu/hr-ft-degF), so the three sources agree within about 3%.", "source": "webelements-pd", "where": "Physical properties table, thermal conductivity", "source_detail": { "title": "WebElements, Palladium physical properties", "id": "WebElements Periodic Table (University of Sheffield mirror)", "url": "https://winter.group.shef.ac.uk/webelements/palladium/physics.html", "year": 2026, "kind": "database", "license": "web database, linked not reproduced" } }, { "benchmark": "electrical_resistivity", "label": "Electrical resistivity", "value": 10.8, "bound": "exact", "unit": "uOhm.cm", "scope": "material", "conditions": { "form": "temper-independent value in the supplier table", "standard_referenced": "ASTM B 589-94 (Refined Palladium)" }, "method": "Value in the supplier's table of properties that do not depend on temper", "status": "ground", "note": "The Deringer-Ney table gives 64.8 uOhm-in alongside 10.8 uOhm-cm. WebElements lists 10.8 x 10^-8 Ohm m (the same value) and Goodfellow lists 105 nOhm.m at 20 degC.", "source": "deringer-ney-pd", "where": "Constant properties table, Electrical Resistivity", "source_detail": { "title": "Deringer-Ney, Palladium (precious metal alloy page)", "id": "Supplier web page; references ASTM B 589-94 (Refined Palladium)", "url": "https://deringerney.com/products/precious-metal-alloys/palladium/", "year": 2026, "kind": "datasheet", "license": "manufacturer document, linked not reproduced" } }, { "benchmark": "electrical_conductivity_iacs", "label": "Electrical conductivity", "value": 16, "bound": "exact", "unit": "% IACS", "scope": "material", "conditions": { "form": "palladium as supplied by Deringer-Ney", "reference": "International Annealed Copper Standard" }, "method": "Value in the supplier's table of properties that do not depend on temper", "status": "ground", "source": "deringer-ney-pd", "where": "Constant properties table, Electrical Conductivity", "source_detail": { "title": "Deringer-Ney, Palladium (precious metal alloy page)", "id": "Supplier web page; references ASTM B 589-94 (Refined Palladium)", "url": "https://deringerney.com/products/precious-metal-alloys/palladium/", "year": 2026, "kind": "datasheet", "license": "manufacturer document, linked not reproduced" } }, { "benchmark": "cte", "label": "Coefficient of linear thermal expansion", "value": 11.8, "bound": "exact", "unit": "ppm/K", "scope": "material", "conditions": { "form": "pure metal", "temperature": "not stated on the page" }, "method": "Value listed in the WebElements physical-properties table as 11.8 x 10^-6 per kelvin", "status": "ground", "note": "Deringer-Ney lists 1.2E-05 per kelvin (6.5E-06 per degF).", "source": "webelements-pd", "where": "Physical properties table, coefficient of linear thermal expansion", "source_detail": { "title": "WebElements, Palladium physical properties", "id": "WebElements Periodic Table (University of Sheffield mirror)", "url": "https://winter.group.shef.ac.uk/webelements/palladium/physics.html", "year": 2026, "kind": "database", "license": "web database, linked not reproduced" } }, { "benchmark": "elastic_modulus", "label": "Young's modulus", "value": 121, "bound": "exact", "unit": "GPa", "scope": "material", "conditions": { "form": "pure metal", "temperature": "not stated on the page" }, "method": "Value listed in the WebElements physical-properties table", "status": "ground", "note": "Goodfellow also lists 121 GPa. Deringer-Ney lists an elastic modulus of 117 GPa (17.0 Msi) and a shear modulus of 44.0 GPa.", "source": "webelements-pd", "where": "Physical properties table, Young's modulus", "source_detail": { "title": "WebElements, Palladium physical properties", "id": "WebElements Periodic Table (University of Sheffield mirror)", "url": "https://winter.group.shef.ac.uk/webelements/palladium/physics.html", "year": 2026, "kind": "database", "license": "web database, linked not reproduced" } }, { "benchmark": "poissons_ratio", "label": "Poisson's ratio", "value": 0.39, "bound": "exact", "unit": "dimensionless", "scope": "material", "conditions": { "form": "palladium as supplied by Deringer-Ney" }, "method": "Value in the supplier's constant-properties table", "status": "ground", "note": "WebElements and Goodfellow also list 0.39.", "source": "deringer-ney-pd", "where": "Second constant-properties table, Poisson's Ratio", "source_detail": { "title": "Deringer-Ney, Palladium (precious metal alloy page)", "id": "Supplier web page; references ASTM B 589-94 (Refined Palladium)", "url": "https://deringerney.com/products/precious-metal-alloys/palladium/", "year": 2026, "kind": "datasheet", "license": "manufacturer document, linked not reproduced" } }, { "benchmark": "tensile_strength_annealed", "label": "Ultimate tensile strength, annealed", "value": 280, "bound": "exact", "unit": "MPa", "scope": "material", "conditions": { "temper": "annealed", "standard_referenced": "ASTM B 589-94 (Refined Palladium)", "test_standard": "not stated on the page" }, "method": "Value in the supplier's annealed-temper tensile table (41 ksi)", "status": "ground", "note": "Goodfellow lists a lower, wider range of 170-210 MPa for tensile strength and 60-120 MPa for yield strength, with no temper stated. The two suppliers disagree, so treat annealed strength as supplier-dependent.", "source": "deringer-ney-pd", "where": "Annealed Temper, tensile properties table", "source_detail": { "title": "Deringer-Ney, Palladium (precious metal alloy page)", "id": "Supplier web page; references ASTM B 589-94 (Refined Palladium)", "url": "https://deringerney.com/products/precious-metal-alloys/palladium/", "year": 2026, "kind": "datasheet", "license": "manufacturer document, linked not reproduced" } }, { "benchmark": "yield_strength_annealed", "label": "0.2% offset yield strength, annealed", "value": 270, "bound": "exact", "unit": "MPa", "scope": "material", "conditions": { "temper": "annealed", "offset": "0.2%" }, "method": "Value in the supplier's annealed-temper tensile table (39 ksi)", "status": "ground", "note": "This is close to the tensile strength of 280 MPa, which is unusual for an annealed metal; Goodfellow's 60-120 MPa yield range is far lower. We could not resolve the difference from the pages alone.", "source": "deringer-ney-pd", "where": "Annealed Temper, tensile properties table", "source_detail": { "title": "Deringer-Ney, Palladium (precious metal alloy page)", "id": "Supplier web page; references ASTM B 589-94 (Refined Palladium)", "url": "https://deringerney.com/products/precious-metal-alloys/palladium/", "year": 2026, "kind": "datasheet", "license": "manufacturer document, linked not reproduced" } }, { "benchmark": "elongation_annealed", "label": "Elongation to failure, annealed", "value": 25, "bound": "exact", "unit": "%", "scope": "material", "conditions": { "temper": "annealed", "gauge_length": "not stated" }, "method": "Value in the supplier's annealed-temper tensile table", "status": "ground", "note": "Goodfellow lists 30-40% elongation at break.", "source": "deringer-ney-pd", "where": "Annealed Temper, tensile properties table", "source_detail": { "title": "Deringer-Ney, Palladium (precious metal alloy page)", "id": "Supplier web page; references ASTM B 589-94 (Refined Palladium)", "url": "https://deringerney.com/products/precious-metal-alloys/palladium/", "year": 2026, "kind": "datasheet", "license": "manufacturer document, linked not reproduced" } }, { "benchmark": "vickers_hardness", "label": "Vickers microhardness, annealed", "value": 40, "bound": "exact", "unit": "HV", "scope": "material", "conditions": { "temper": "annealed", "load": "not stated on the page" }, "method": "Value in the supplier's annealed-temper hardness table (Knoop microhardness is 50 HK in the same table)", "status": "ground", "note": "Goodfellow lists about 55 HV for annealed palladium.", "source": "deringer-ney-pd", "where": "Annealed Temper, hardness table", "source_detail": { "title": "Deringer-Ney, Palladium (precious metal alloy page)", "id": "Supplier web page; references ASTM B 589-94 (Refined Palladium)", "url": "https://deringerney.com/products/precious-metal-alloys/palladium/", "year": 2026, "kind": "datasheet", "license": "manufacturer document, linked not reproduced" } }, { "benchmark": "contact_resistance", "label": "Contact resistance at 30 gf", "value": 6, "bound": "exact", "unit": "mOhm", "scope": "material", "conditions": { "contact_force": "30 gf", "state": "as listed by the supplier; the oxidised case (1,000 h at 150 degC) also reads 6 mOhm" }, "method": "Supplier contact-resistance test (method details not stated on the page)", "status": "ground", "note": "After 720 h at 50 degC in flowers of sulfur the same table reads 10 mOhm.", "source": "deringer-ney-pd", "where": "Second constant-properties table, Contact resistance rows", "source_detail": { "title": "Deringer-Ney, Palladium (precious metal alloy page)", "id": "Supplier web page; references ASTM B 589-94 (Refined Palladium)", "url": "https://deringerney.com/products/precious-metal-alloys/palladium/", "year": 2026, "kind": "datasheet", "license": "manufacturer document, linked not reproduced" } }, { "benchmark": "lattice_parameter", "label": "Lattice parameter (face-centred cubic)", "value": 3.891, "bound": "exact", "unit": "angstrom", "scope": "material", "conditions": { "temperature": "room temperature", "structure": "FCC" }, "method": "Value listed in the supplier's General Properties table", "status": "ground", "note": "Deringer-Ney lists 3.89 angstrom.", "source": "goodfellow-pd", "where": "General Properties table, Crystal Structure", "source_detail": { "title": "Goodfellow, High-Purity Palladium Metal", "id": "Supplier web page, General and Mechanical Properties tables", "url": "https://www.goodfellow.com/usa/material/precious-metals/palladium", "year": 2026, "kind": "datasheet", "license": "manufacturer document, linked not reproduced" } }, { "benchmark": "h_to_pd_ratio_beta", "label": "Hydrogen-to-palladium atom ratio, beta (hydride) phase", "value": 0.7, "bound": "exact", "unit": "H/Pd", "scope": "material", "conditions": { "temperature": "25 degC", "hydrogen_pressure": "1 bar", "phase": "beta" }, "method": "Statement in the introduction of an open-access research paper on palladium membranes (\"about 0.7\")", "status": "ground", "note": "The same passage gives about 0.015 for the hydrogen-poor alpha phase under the same conditions. This is a literature statement in the paper, not a measurement made by its authors.", "source": "ma2021-pd-membranes", "where": "Introduction, Pd-H phase behaviour", "source_detail": { "title": "Thin robust Pd membranes for low-temperature application", "id": "doi:10.1039/d1ra06192e (RSC Advances 11(58), 36617-36624; PMC9043342)", "url": "https://pmc.ncbi.nlm.nih.gov/articles/PMC9043342", "year": 2021, "kind": "paper", "license": "Royal Society of Chemistry copyright shown; open access on PubMed Central; no licence named on the page we read" } }, { "benchmark": "h_to_pd_ratio_alpha", "label": "Hydrogen-to-palladium atom ratio, alpha phase", "value": 0.015, "bound": "exact", "unit": "H/Pd", "scope": "material", "conditions": { "temperature": "25 degC", "hydrogen_pressure": "1 bar", "phase": "alpha" }, "method": "Statement in the introduction of an open-access research paper on palladium membranes (\"about 0.015\")", "status": "ground", "source": "ma2021-pd-membranes", "where": "Introduction, Pd-H phase behaviour", "source_detail": { "title": "Thin robust Pd membranes for low-temperature application", "id": "doi:10.1039/d1ra06192e (RSC Advances 11(58), 36617-36624; PMC9043342)", "url": "https://pmc.ncbi.nlm.nih.gov/articles/PMC9043342", "year": 2021, "kind": "paper", "license": "Royal Society of Chemistry copyright shown; open access on PubMed Central; no licence named on the page we read" } }, { "benchmark": "hydride_critical_temp", "label": "Temperature below which alpha and beta phases coexist", "value": 293, "bound": "exact", "unit": "degC", "scope": "material", "conditions": { "hydrogen_pressure": "below 20 bar", "effect": "beta phase nucleates and grows in the alpha phase" }, "method": "Statement in the introduction of an open-access research paper on palladium membranes (\"about 293 degC\")", "status": "ground", "note": "The paper adds that pure Pd membranes are therefore often limited to operating temperatures above 300 degC.", "source": "ma2021-pd-membranes", "where": "Introduction, critical temperature and pressure", "source_detail": { "title": "Thin robust Pd membranes for low-temperature application", "id": "doi:10.1039/d1ra06192e (RSC Advances 11(58), 36617-36624; PMC9043342)", "url": "https://pmc.ncbi.nlm.nih.gov/articles/PMC9043342", "year": 2021, "kind": "paper", "license": "Royal Society of Chemistry copyright shown; open access on PubMed Central; no licence named on the page we read" } }, { "benchmark": "hydride_volume_expansion", "label": "Volume expansion in the alpha-to-beta transition", "value": 10, "bound": "exact", "unit": "% (stated as 'over 10%')", "scope": "material", "conditions": { "transition": "alpha to beta palladium hydride", "note": "lower bound only; the paper gives no upper value" }, "method": "Statement in the paper (\"the expansion of volume for the phase transition is over 10%\")", "status": "ground", "note": "The paper links this expansion to internal stress, warping and fracture of pure Pd membranes, and reports that 2 mm outer-diameter hollow fibre membranes less than 4 micrometres thick resisted embrittlement below 100 degC.", "source": "ma2021-pd-membranes", "where": "Introduction and Results on embrittlement", "source_detail": { "title": "Thin robust Pd membranes for low-temperature application", "id": "doi:10.1039/d1ra06192e (RSC Advances 11(58), 36617-36624; PMC9043342)", "url": "https://pmc.ncbi.nlm.nih.gov/articles/PMC9043342", "year": 2021, "kind": "paper", "license": "Royal Society of Chemistry copyright shown; open access on PubMed Central; no licence named on the page we read" } }, { "benchmark": "dissolved_h2_pressure_out", "label": "Dissolved-hydrogen partial pressure after a Pd-Ag separator", "value": 0.5, "bound": "exact", "unit": "psia (stated as 'less than')", "scope": "material", "conditions": { "inlet_partial_pressure": "60 psia", "water_temperature": "75 degF", "water_flow": "10 ml per minute", "membrane": "75% palladium-25% silver alloy tubes coated with palladium black, 18 tubes, 1/8 in outer diameter, 10 mil wall" }, "method": "NASA Tech Brief describing a separator built by The Garrett Corporation under contract to the Manned Spacecraft Center", "status": "ground", "note": "The same brief reports a test unit ran more than 5 months (3700 hours) without loss of efficiency. The separator was devised to remove dissolved hydrogen from water produced by fuel cells with an alkaline electrolyte.", "source": "nasa-tech-brief-1969", "where": "Article text, paragraph on the fabricated separator", "source_detail": { "title": "Device Separates Hydrogen from Solution in Water at Ambient Temperatures", "id": "NASA Tech Brief B69-10635 (MSC-13335), November 1969", "url": "https://ntrs.nasa.gov/api/citations/19690000580/downloads/19690000580.pdf", "year": 1969, "kind": "report", "license": "public domain (NASA)" } }, { "benchmark": "pd_in_mobile_phone_pcb", "label": "Palladium in printed circuit boards of mobile phones", "value": 119, "bound": "exact", "unit": "ppm", "scope": "material", "conditions": { "sample": "printed circuit boards from 30 mobile phones", "method": "boards milled, cryo-milled, leached with aqua regia, leachate analysed", "note": "the study separates mobile phones from smartphones" }, "method": "Published waste-electronics study (aqua regia leach, then solution analysis)", "status": "ground", "note": "Same abstract gives 20 ppm for 10 internet routers and 55 ppm for 30 smartphones, so the palladium level was lower in the newer smartphone boards.", "source": "holgersson2018", "where": "Abstract (precious-metal concentrations in PCBs)", "source_detail": { "title": "Analysis of the metal content of small-size Waste Electric and Electronic Equipment (WEEE) printed circuit-boards part 1: Internet routers, mobile phones and smartphones", "id": "doi:10.1016/j.resconrec.2017.02.011 (Resources, Conservation and Recycling 133, 300-308)", "url": "https://research.chalmers.se/en/publication/502981", "year": 2018, "kind": "paper", "license": "publisher article; abstract read on the Chalmers research record, linked not reproduced" } }, { "benchmark": "pd_in_smartphone_pcb", "label": "Palladium in printed circuit boards of smartphones", "value": 55, "bound": "exact", "unit": "ppm", "scope": "material", "conditions": { "sample": "printed circuit boards from 30 smartphones", "method": "boards milled, cryo-milled, leached with aqua regia, leachate analysed" }, "method": "Published waste-electronics study (aqua regia leach, then solution analysis)", "status": "ground", "source": "holgersson2018", "where": "Abstract (precious-metal concentrations in PCBs)", "source_detail": { "title": "Analysis of the metal content of small-size Waste Electric and Electronic Equipment (WEEE) printed circuit-boards part 1: Internet routers, mobile phones and smartphones", "id": "doi:10.1016/j.resconrec.2017.02.011 (Resources, Conservation and Recycling 133, 300-308)", "url": "https://research.chalmers.se/en/publication/502981", "year": 2018, "kind": "paper", "license": "publisher article; abstract read on the Chalmers research record, linked not reproduced" } } ], "corrosion": [ { "environment": "Acids, alkalis and organic solvents", "headline": "Palladium dissolves in aqua regia and fused alkalies but not in organic acids.", "effect": "PubChem, quoting Hawley's Condensed Chemical Dictionary, lists palladium as soluble in aqua regia and fused alkalies and insoluble in organic acids. A Merck Index entry quoted there says that at a red heat the metal converts to the monoxide. We did not find a corrosion-rate table.", "rating": "unknown", "conditions": { "basis": "handbook statements quoted in PubChem", "rates": "none found" }, "source": "pubchem-pd", "where": "Experimental Properties > Solubility; Hazardous Reactivities and Incompatibilities" }, { "environment": "Hydrogen gas", "headline": "Not corrosion in the usual sense: hydrogen enters the lattice and can distort and crack pure palladium.", "effect": "Below about 293 degC and under 20 bar of hydrogen, the hydrogen-rich beta phase grows inside the hydrogen-poor alpha phase. The two share a crystal symmetry but differ in volume, and the expansion on transition is over 10%. Hydrogen embrittlement is reported to warp and destroy pure Pd membranes. NASA's permeation report notes that palladium is typically alloyed with silver to protect its strength and shape-holding against hydrogen.", "rating": "severe", "conditions": { "temperature": "below about 293 degC", "hydrogen_pressure": "below 20 bar", "metal": "pure palladium, not alloyed" }, "source": "ma2021-pd-membranes", "where": "Introduction and Results; NASA/TM-2019-220189 Introduction" } ], "risks": { "hazards": [ { "text": "PubChem aggregates 616 company reports to the ECHA inventory: 59.3% (365 reports) say the chemical does not meet GHS hazard criteria, and 31.5% classify it as a flammable solid (H228, signal word Danger). Because the reports disagree, the classification depends on the supplier and the form of the metal.", "ghs": [ "H228" ], "source": "pubchem-pd", "where": "Safety and Hazards > Hazards Identification > GHS Classification" }, { "text": "Palladium dust is combustible when exposed to heat or flame and can be a fire and explosive hazard. Finely divided palladium (palladium black) used as a hydrogenation catalyst is usually pyrophoric. A user report in PubChem describes palladium on carbon (10% wet) starting a small fire when added to a flask containing hydrogen and methanol.", "ghs": [], "source": "pubchem-pd", "where": "Hazards Summary; Fire Potential; Reactivity Alerts" }, { "text": "Possible skin sensitiser. Contact dermatitis has been associated with metallic palladium, especially palladium alloys; occupational asthma has been reported but is very rare.", "ghs": [], "source": "pubchem-pd", "where": "Hazards Summary; Skin, Eye, and Respiratory Irritations" } ], "failure_risks": [ { "mode": "Hydrogen embrittlement and warping of pure palladium", "trigger": "Hydrogen absorption below about 293 degC and under 20 bar, which forms the beta hydride phase alongside the alpha phase", "consequence": "The lattice swells by more than 10% where beta forms, so internal stress builds and pure Pd membranes warp and fracture.", "severity": "high", "source": "ma2021-pd-membranes", "where": "Introduction and Results" }, { "mode": "Loss of strength and shape-holding in hydrogen", "trigger": "Exposure of thin pure palladium purification membranes to hydrogen", "consequence": "NASA notes membranes are typically alloyed with silver to protect against hydrogen affecting the strength and shape-holding of the metal; the silver fraction can approach 60 percent, with 25 percent giving a good balance.", "severity": "moderate", "source": "smith2019-nasa-tm", "where": "Introduction" } ], "side_effects": [ { "text": "Palladium black on the surface of a separator tube was bonded by reducing applied palladium chloride in hydrogen, at nominal loadings of 2 milligrams per square centimetre of alloy surface. Tubes much larger than 1/8 in. would be less efficient and smaller ones could not be coated inside.", "affects": "Design of the 1969 fuel-cell water separator", "source": "nasa-tech-brief-1969", "where": "Article text" } ], "handling": [ { "text": "Dust is combustible; finely divided palladium catalysts are usually pyrophoric and need appropriate handling precautions. PubChem lists incompatibilities with arsenic, carbon, ozonides, methanol and sulfur, and reports explosive reaction with hydrogen and hydrogen peroxide.", "source": "pubchem-pd", "where": "Fire Potential; Explosive Limits and Potential; Hazardous Reactivities and Incompatibilities" } ], "mitigations": [ { "text": "PubChem's disposal note advises using an alternative chemical with less propensity for occupational exposure where possible and recycling unused portions.", "source": "pubchem-pd", "where": "Accidental Release Measures > Disposal Methods" } ] }, "uses": [ { "application": "electronics-and-chips", "device": "Multilayer ceramic capacitors and hybridised integrated circuits", "example": "The USGS lists electronic applications of platinum-group metals such as computer hard disks, hybridized integrated circuits and multilayer ceramic capacitors. Palladium is one of the six metals in that chapter.", "source": "usgs-mcs2025-pgm", "where": "Domestic Production and Use" }, { "application": "electronics-and-chips", "device": "Printed circuit boards of mobile phones", "example": "A Swedish study aqua-regia-leached boards from 30 mobile phones and 30 smartphones and found 119 ppm and 55 ppm palladium respectively.", "source": "holgersson2018", "where": "Abstract" }, { "application": "electronics-and-chips", "device": "Electrical contact material (supplier data for palladium)", "example": "Deringer-Ney lists contact-resistance results for its palladium: 6 mOhm at 30 gf, unchanged after 1,000 h at 150 degC and 10 mOhm after 720 h in flowers of sulfur at 50 degC. The page does not name a product.", "source": "deringer-ney-pd", "where": "Second constant-properties table" }, { "application": "propulsion-and-tanks", "device": "Palladium-silver separator for dissolved hydrogen in spacecraft fuel-cell water (NASA-sponsored, 1969 design)", "example": "A separator of 75% palladium-25% silver alloy with palladium black coatings was built by The Garrett Corporation under contract to the Manned Spacecraft Center to remove dissolved hydrogen from alkaline fuel-cell water. A test unit ran more than 3700 hours.", "source": "nasa-tech-brief-1969", "where": "Article text and Source line" }, { "application": "cryogenic-fuel", "device": "Hydrogen purification membranes (laboratory and industrial)", "example": "NASA Glenn's 2019 report says palladium is commonly used to purify hydrogen because only hydrogen readily passes through the bulk metal, and models permeation through a palladium-silver alloy.", "source": "smith2019-nasa-tm", "where": "Introduction and Summary" }, { "application": "electronics-and-chips", "device": "Catalysts for vehicles, bulk chemicals and petroleum refining", "example": "The USGS lists catalytic converters as the leading domestic use of platinum-group metals and names catalysts for bulk-chemical production and petroleum refining. Palladium has substituted for platinum in most gasoline-engine catalytic converters.", "source": "usgs-mcs2025-pgm", "where": "Domestic Production and Use; Substitutes" } ], "supply": [ { "subject": "Palladium", "abundance": "World mine production of palladium was 208,000 kg in 2023 and 190,000 kg (estimated) in 2024, of which Russia mined 75,000 kg, South Africa 72,000 kg, Canada 15,000 kg, Zimbabwe 15,000 kg and the United States 8,000 kg. For platinum the 2024 estimate was 170,000 kg, of which South Africa mined 120,000 kg and Russia 18,000 kg. PGM reserves (all platinum-group metals together, not palladium alone) are more than 81,000,000 kg, with the largest in South Africa (63,000,000 kg) and Russia (16,000,000 kg); world PGM resources are more than 100 million kg, largest in the Bushveld Complex of South Africa.", "producers": [ { "country": "Russia", "share_percent": 39.5, "year": 2024 }, { "country": "South Africa", "share_percent": 37.9, "year": 2024 }, { "country": "Canada", "share_percent": 7.9, "year": 2024 }, { "country": "Zimbabwe", "share_percent": 7.9, "year": 2024 }, { "country": "United States", "share_percent": 4.2, "year": 2024 }, { "country": "Other countries", "share_percent": 2.2, "year": 2024 } ], "critical_lists": [], "recycling": "About 120,000 kg of palladium and platinum were recovered globally from new and old scrap in 2024, including about 45,000 kg of palladium and 8,500 kg of platinum from automobile catalytic converters in the United States (USGS).", "substitutes": [ "Palladium has substituted for platinum in most gasoline-engine catalytic converters; about 25% of palladium can routinely be substituted for platinum in diesel converters, up to 50% in some applications.", "For some industrial end uses one PGM can substitute for another, with losses in efficiency." ], "source": "usgs-mcs2025-pgm", "where": "World Mine Production and Reserves table; World Resources; Recycling; Substitutes. Producer shares are calculated by Space Mushroom as each country's 2024e kg divided by the 190,000 kg world total, so they sum to about 99.6% because the USGS total is rounded." }, { "subject": "Palladium (United States)", "abundance": "US mine production of palladium was 8,000 kg (estimated) in 2024, down from 10,300 kg in 2023; US apparent consumption was 83,000 kg (estimated) and net import reliance 36% of apparent consumption in 2024. Palladium imports in 2020-23 came from Russia (32%), South Africa (32%), Belgium (8%) and Italy (8%).", "producers": [], "critical_lists": [], "recycling": "See above: about 45,000 kg of palladium recovered from US automobile catalytic converters in 2024.", "substitutes": [], "source": "usgs-mcs2025-pgm", "where": "Salient Statistics table; Import Sources (2020-23). The USGS also reports Russia as the world's leading producer of mined palladium and South Africa as the leading producer of PGM-containing mined material." } ], "media": [], "documents": [ { "title": "WebElements: Palladium, the essentials", "type": "database", "url": "https://winter.group.shef.ac.uk/webelements/palladium/", "year": 2026 }, { "title": "WebElements: Palladium, crystal structure", "type": "database", "url": "https://winter.group.shef.ac.uk/webelements/palladium/crystal_structure.html", "year": 2026 }, { "title": "USGS Mineral Commodity Summaries 2025: Platinum-Group Metals", "type": "report", "url": "https://pubs.usgs.gov/periodicals/mcs2025/mcs2025-platinum-group.pdf", "year": 2025 }, { "title": "PubChem compound record: Palladium (CID 23938)", "type": "database", "url": "https://pubchem.ncbi.nlm.nih.gov/compound/Palladium", "year": 2026 }, { "title": "Deringer-Ney: Palladium (precious metal alloy datasheet page)", "type": "datasheet", "url": "https://deringerney.com/products/precious-metal-alloys/palladium/", "year": 2026 }, { "title": "Goodfellow: High-Purity Palladium Metal", "type": "datasheet", "url": "https://www.goodfellow.com/usa/material/precious-metals/palladium", "year": 2026 }, { "title": "WebElements: Palladium physical properties", "type": "database", "url": "https://winter.group.shef.ac.uk/webelements/palladium/physics.html", "year": 2026 }, { "title": "Thin robust Pd membranes for low-temperature application (RSC Advances, PMC9043342)", "type": "paper", "url": "https://pmc.ncbi.nlm.nih.gov/articles/PMC9043342", "year": 2021 }, { "title": "NASA/TM-2019-220189: Permeation Rate Equations for Hydrogen and Deuterium in a Palladium-Silver Alloy", "type": "report", "url": "https://ntrs.nasa.gov/api/citations/20190030498/downloads/20190030498.pdf", "year": 2019 }, { "title": "NASA Tech Brief B69-10635: Device Separates Hydrogen from Solution in Water at Ambient Temperatures", "type": "report", "url": "https://ntrs.nasa.gov/api/citations/19690000580/downloads/19690000580.pdf", "year": 1969 }, { "title": "Analysis of the metal content of small-size WEEE printed circuit-boards part 1 (Holgersson et al.; Chalmers record)", "type": "paper", "url": "https://research.chalmers.se/en/publication/502981", "year": 2018 } ], "gaps": [ "The 2026 USGS palladium group metals PDF (https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-palladium-group-metals.pdf) returned a Page Not Found page in this run, so the refining route and 2026 supply figures were not read. The recipe names the ore source from Wikipedia only (nickel-copper deposits and catalytic-converter recycling), and no refining process is sourced.", "Connector plating: no source opened states palladium or palladium-alloy connector plating directly; only Deringer-Ney contact-resistance data for palladium were found, so that use is described as electrical-contact material.", "Multilayer ceramic capacitors: the USGS only lists the capacitor use in a sentence. No source with the palladium or palladium-silver electrode content, or the mass of palladium per capacitor, was found.", "Annealed mechanical properties disagree: Deringer-Ney gives 280 MPa tensile and 270 MPa yield (annealed), Goodfellow gives 170-210 MPa and 60-120 MPa (temper not stated). No standard or paper was found to settle which is right, and no cold-worked values were sourced.", "No density, conductivity or modulus value was found with an explicit measurement temperature and method; the WebElements page states none, and the PubChem handbook entries give only the citation.", "Hydrogen solubility versus pressure and temperature (the pressure-composition isotherms) and a numerical lattice parameter for the beta phase were not obtained; the open-access paper gives the H/Pd ratios but no lattice constants.", "The NASA 2019 permeation equations (constants 4.22e-6 and 704 K for hydrogen, 2.12e-6 and 468 K for deuterium) were read from a text extraction in which the exponent layout is garbled, so they were not entered as a property. Check the PDF before using them.", "The 1969 NASA separator is a fuel-cell water device from a design brief. No source was found on palladium hydrogen handling on current spacecraft (for example ISS life-support hardware), so no claim about present use is made.", "Catalytic role: only the USGS use list was opened. No source on hydrogenation, cross-coupling or catalytic-converter chemistry (what palladium actually does, loadings, poisoning) was fetched; the Nobel Foundation release could not be opened (HTTP 403).", "USGS Mineral Commodity Summaries 2026 could not be read (the file fetched was a single page), so supply data are for 2024 estimates from the 2025 edition. The USGS critical minerals list status for palladium was not checked.", "The Jandric et al. pXRF study of 45 phones (1998-2021) was found only through search-result text and could not be opened, so it is not cited. Only the Holgersson et al. abstract (read on the Chalmers page) is used for mobile-phone palladium.", "No ECHA registration dossier or safety data sheet was opened; hazard data are PubChem aggregates only. No space-environment data (atomic oxygen, radiation, outgassing, vacuum cold welding) for palladium were found. No prices are shown." ], "story": { "why": "Palladium is a platinum-group metal with a face-centred cubic crystal structure and a lattice parameter of 3.891 angstroms. It is dense (12.02 g/cm3), melts at 1554.9 degC and boils at 2963 degC. Annealed, it is soft: a supplier datasheet gives a tensile strength of 280 MPa, 25% elongation and a Vickers hardness of 40. Its electrical conductivity is 16% of the International Annealed Copper Standard, and its thermal conductivity is about 72 W/(m.K). What sets it apart is hydrogen. The metal absorbs hydrogen into its crystal lattice, up to about 0.7 hydrogen atoms per palladium atom at 25 degC and 1 bar in the beta phase, and only hydrogen readily passes through the bulk metal, which is why it is used to purify hydrogen. The same absorption swells the lattice by more than 10% in the alpha-to-beta transition and can crack pure palladium, so purification membranes are usually alloyed with silver.", "uses": [ { "where": "Capacitors and chips", "line": "The USGS lists multilayer ceramic capacitors and hybridised integrated circuits among electronic uses of the platinum-group metals, which include palladium. It gives no palladium content per part." }, { "where": "Mobile-phone circuit boards", "line": "A published study leached boards from 30 mobile phones and 30 smartphones in aqua regia and measured palladium at 119 ppm and 55 ppm. Older phone boards held more palladium than newer ones." }, { "where": "Spacecraft fuel-cell water", "line": "In 1969 a separator of palladium-silver alloy coated with palladium black was built under a Manned Spacecraft Center contract to remove dissolved hydrogen from alkaline fuel-cell water. A test unit ran more than 3700 hours without loss of efficiency." }, { "where": "Catalysts", "line": "The USGS names catalytic converters as the leading domestic use of platinum-group metals, and lists catalysts for bulk chemicals and petroleum refining. Palladium has replaced platinum in most gasoline-engine converters." } ], "can_do": [ { "label": "Hydrogen passage", "line": "The 1969 NASA-sponsored separator, made from 75% palladium-25% silver tubes with palladium black, lowered the partial pressure of hydrogen dissolved in water from 60 psia to less than 0.5 psia at 75 degF and 10 ml per minute of flow.", "scope": "material", "value": "Dissolved H2 from 60 to under 0.5 psia" }, { "label": "Hydrogen uptake", "line": "At 25 degC and 1 bar the beta phase holds a hydrogen-to-palladium ratio of about 0.7, against about 0.015 for the alpha phase, according to an open-access paper on palladium membranes.", "scope": "material", "value": "About 0.7 H per Pd" }, { "label": "Conducting", "line": "Deringer-Ney gives a resistivity of 10.8 microohm-cm and 16% IACS conductivity. WebElements gives a thermal conductivity of 72 W/(m.K), with Goodfellow at 71.8 and Deringer-Ney at 70.", "scope": "material", "value": "10.8 microohm-cm" }, { "label": "Stability of contacts", "line": "The same supplier lists a contact resistance of 6 mOhm at 30 gf that stayed at 6 mOhm after 1,000 hours at 150 degC, and 10 mOhm after 720 hours in flowers of sulfur at 50 degC.", "scope": "material", "value": "6 mOhm at 30 gf" }, { "label": "Supply", "line": "The USGS estimates world mine production of palladium at 190,000 kg in 2024, with Russia at 75,000 kg and South Africa at 72,000 kg.", "scope": "material", "value": "190,000 kg in 2024" } ], "compare": "Within the sources collected here, palladium's 2024 world mine production (190,000 kg, estimated) is slightly above platinum's 170,000 kg, and palladium is far more concentrated in Russia (75,000 kg) than platinum is (18,000 kg), where South Africa leads with 120,000 kg. The 2019 NASA report says palladium is commonly alloyed with silver for hydrogen membranes, with 25 percent silver a good balance. No source collected here compares palladium's mechanical properties with those of other metals, so no such comparison is made.", "compare_rows": [ { "label": "Density", "benchmark": "density", "scope": "material" }, { "label": "Melting point", "benchmark": "melting_point", "scope": "material" }, { "label": "Thermal conductivity", "benchmark": "thermal_conductivity", "scope": "material" } ], "handling": [ "Treat fine palladium powders and palladium black as pyrophoric; keep them away from methanol and hydrogen together.", "Expect a possible skin sensitiser, especially in palladium alloys.", "Plan for hydrogen to be absorbed and for the lattice to swell; alloy with silver or keep membranes away from the cool, pressurised alpha-beta region.", "Recycle scrap; the USGS counts about 45,000 kg of palladium recovered from US car catalysts in 2024." ], "good_for": [ "Catalysis and hydrogen separation. Only hydrogen readily passes through bulk palladium, and a palladium-silver separator ran 3700 hours in a NASA-sponsored test.", "Electrical contacts. A supplier lists 6 mOhm contact resistance at 30 gf, and 16% IACS conductivity.", "Recyclability. About 120,000 kg of palladium and platinum were recovered from scrap worldwide in 2024." ], "watch_out": [ "Hydrogen embrittlement. Pure palladium expands by more than 10% in volume when the hydride phase forms, and membranes warp and fracture.", "Supply concentration. Russia and South Africa together make up about 77% of 2024 estimated world mine production (calculated from the USGS table).", "Spread in datasheet strength. Two suppliers disagree on annealed strength (280 MPa against 170-210 MPa), so check the grade and temper.", "Powder fire risk. Palladium black is usually pyrophoric." ], "verdict": "Palladium is a dense, soft, catalytic metal that is used where hydrogen has to be passed, purified or reacted, and where stable electrical contacts are needed, but it absorbs hydrogen enough to swell and crack when used unalloyed, and mining is concentrated in Russia and South Africa. The spacecraft evidence found here is one 1969 NASA-sponsored fuel-cell water separator and a 2019 NASA permeation model; no flight data on palladium in modern spacecraft were found.", "recipe": { "line": "Palladium is the element Pd, atomic number 46, a platinum-group metal with cubic close-packed crystals (ccp, space group Fm-3m, WebElements). Wikipedia says the most important commercial sources are nickel-copper deposits, and that recycling, mostly of scrapped catalytic converters, is also a source. The refining route was not read in this run; the Wikipedia history section describes only the early laboratory isolation from aqua regia, which is not a production process.", "parts": [ { "name": "Palladium", "symbol": "Pd", "role": "The whole material. WebElements prints the relative atomic mass on its main page.", "atoms": 1, "atomic_weight": 106.42 } ] }, "risk_groups": [ { "title": "For people", "lead": "Solid palladium is a mild concern, but the dust and especially palladium black catalysts can ignite, and the metal can sensitise skin.", "points": [ { "label": "Classification", "line": "PubChem aggregates 616 supplier reports: 59.3% say palladium does not meet GHS hazard criteria and 31.5% label it a flammable solid (H228). The classification depends on the supplier and the form." }, { "label": "Skin", "line": "Contact dermatitis has been associated with metallic palladium, especially palladium alloys, and the metal is called a possible skin sensitiser. Occupational asthma has been reported but is very rare." }, { "label": "Fire", "line": "Dust is combustible, and finely divided palladium black used as a hydrogenation catalyst is usually pyrophoric. A reported fire started when 10% palladium on carbon met methanol in a hydrogen-filled flask." } ], "level": 2, "verdict": "Mixed classification; fine powder burns" }, { "title": "If it fails", "lead": "The documented failure is hydrogen embrittlement of pure palladium, studied in membranes and not in spacecraft parts.", "points": [ { "label": "Hydrogen embrittlement", "line": "Below about 293 degC and under 20 bar of hydrogen, the hydrogen-rich beta phase grows inside the hydrogen-poor alpha phase. The lattice expands by more than 10% in the transition, and the resulting stress warps and destroys pure Pd membranes." }, { "label": "Alloy fix", "line": "NASA notes that palladium purification membranes are typically alloyed with silver to protect strength and shape against hydrogen, and that 25 percent silver gives a good balance." }, { "label": "Thin tubes", "line": "In the same paper, hollow fibre membranes 2 mm in outer diameter and under 4 micrometres thick resisted embrittlement below 100 degC." } ] }, { "title": "Handling and storage", "points": [ { "label": "Catalyst powders", "line": "Treat palladium black and palladium on carbon as pyrophoric and keep them away from methanol and other organic solvents when hydrogen is present." }, { "label": "Incompatibilities", "line": "PubChem lists arsenic, carbon, ozonides, methanol and sulfur as incompatible, and an explosive reaction with hydrogen and hydrogen peroxide." }, { "label": "Disposal", "line": "Recycle unused portions where possible, as PubChem's disposal note advises." } ] } ] }, "updated": "2026-10-17", "review": { "status": "draft", "method": "assistant", "checked_values": 22, "unreachable": 4, "caveats": 6, "note": "Written by an AI assistant on 2026-10-17. USGS table values were read in text extracted from the PDF; PubChem values were read in its JSON record; the Holgersson abstract was read in the page HTML; NASA brief and NASA TM were read in extracted PDF text. Deringer-Ney, Goodfellow, WebElements and the RSC Advances paper were read once through a web-page summary and not independently re-read. Unreachable: USGS MCS 2026, MDPI Recycling 2020, Jandric et al. (RWTH), Nobel Foundation release. No values were taken from memory." }, "sources": { "webelements-palladium-main": { "title": "Palladium - 46Pd: the essentials (WebElements, relative atomic mass)", "url": "https://winter.group.shef.ac.uk/webelements/palladium/", "year": 2026, "kind": "database", "license": "WebElements, free online reference" }, "webelements-palladium-crystal": { "title": "Palladium - 46Pd: crystal structure (WebElements)", "url": "https://winter.group.shef.ac.uk/webelements/palladium/crystal_structure.html", "year": 2026, "kind": "database", "license": "WebElements, free online reference" }, "wikipedia-palladium": { "title": "Palladium (Wikipedia, occurrence and history sections)", "url": "https://en.wikipedia.org/wiki/Palladium", "year": 2026, "kind": "web", "license": "CC BY-SA 4.0" }, "usgs-mcs2025-pgm": { "title": "Mineral Commodity Summaries 2025, Platinum-Group Metals", "id": "USGS MCS 2025, pp. 136-137 (data to 2024)", "url": "https://pubs.usgs.gov/periodicals/mcs2025/mcs2025-platinum-group.pdf", "year": 2025, "kind": "report", "license": "public domain (USGS)" }, "pubchem-pd": { "title": "PubChem compound record, Palladium (CID 23938)", "id": "CID 23938; CAS 7440-05-3", "url": "https://pubchem.ncbi.nlm.nih.gov/compound/Palladium", "year": 2026, "kind": "database", "license": "public domain (NCBI); cited handbooks are not reproduced" }, "webelements-pd": { "title": "WebElements, Palladium physical properties", "id": "WebElements Periodic Table (University of Sheffield mirror)", "url": "https://winter.group.shef.ac.uk/webelements/palladium/physics.html", "year": 2026, "kind": "database", "license": "web database, linked not reproduced" }, "deringer-ney-pd": { "title": "Deringer-Ney, Palladium (precious metal alloy page)", "id": "Supplier web page; references ASTM B 589-94 (Refined Palladium)", "url": "https://deringerney.com/products/precious-metal-alloys/palladium/", "year": 2026, "kind": "datasheet", "license": "manufacturer document, linked not reproduced" }, "goodfellow-pd": { "title": "Goodfellow, High-Purity Palladium Metal", "id": "Supplier web page, General and Mechanical Properties tables", "url": "https://www.goodfellow.com/usa/material/precious-metals/palladium", "year": 2026, "kind": "datasheet", "license": "manufacturer document, linked not reproduced" }, "ma2021-pd-membranes": { "title": "Thin robust Pd membranes for low-temperature application", "id": "doi:10.1039/d1ra06192e (RSC Advances 11(58), 36617-36624; PMC9043342)", "url": "https://pmc.ncbi.nlm.nih.gov/articles/PMC9043342", "year": 2021, "kind": "paper", "license": "Royal Society of Chemistry copyright shown; open access on PubMed Central; no licence named on the page we read" }, "smith2019-nasa-tm": { "title": "Permeation Rate Equations for Hydrogen and Deuterium in a Palladium-Silver Alloy", "id": "NASA/TM-2019-220189, NTRS 20190030498", "url": "https://ntrs.nasa.gov/api/citations/20190030498/downloads/20190030498.pdf", "year": 2019, "kind": "report", "license": "public domain (NASA)" }, "nasa-tech-brief-1969": { "title": "Device Separates Hydrogen from Solution in Water at Ambient Temperatures", "id": "NASA Tech Brief B69-10635 (MSC-13335), November 1969", "url": "https://ntrs.nasa.gov/api/citations/19690000580/downloads/19690000580.pdf", "year": 1969, "kind": "report", "license": "public domain (NASA)" }, "holgersson2018": { "title": "Analysis of the metal content of small-size Waste Electric and Electronic Equipment (WEEE) printed circuit-boards part 1: Internet routers, mobile phones and smartphones", "id": "doi:10.1016/j.resconrec.2017.02.011 (Resources, Conservation and Recycling 133, 300-308)", "url": "https://research.chalmers.se/en/publication/502981", "year": 2018, "kind": "paper", "license": "publisher article; abstract read on the Chalmers research record, linked not reproduced" } }, "license": "CC-BY-4.0", "url": "https://spacemushroom.com/profiles/palladium/" }