{ "spore": "profile", "id": "nickel-oxide", "spore_version": "0.2", "family": "oxide-ceramics", "name": "Nickel oxide", "abbreviation": "NiO", "role": "p-type oxide for transparent layers, solid oxide fuel cell anodes and oxide scales on nickel; carcinogen", "category": "ceramics", "type": "oxides", "summary": "Nickel(II) oxide (NiO) is a green-to-black oxide with a face-centred cubic rock-salt structure. Its lattice constant is 4.169 Å at 298 K, its density is 6.67 g/cm3, and one supplier safety data sheet gives a melting point of 1984 °C. It is practically insoluble in water (0.00003 g/l at 20 °C). Sputtered NiO films are p-type conductors: a 110 nm film on glass reached 7.2 S/cm with 40 percent average transmittance, and a 100 nm RF-sputtered film reached 9.09 S/cm with 69 percent. Porous Ni/YSZ and NiO/YSZ composites have been studied for solid oxide fuel cell anodes. Nickel heated in oxygen forms a NiO scale that grows outward and carries a compressive grain-boundary stress of about 10 MN/m2 at 1000 °C. NiO is a carcinogen hazard: the Sigma-Aldrich safety data sheet gives H350, and IARC places nickel compounds in Group 1.\n", "best_for": "p-type transparent conducting films and nickel-based solid oxide fuel cell anode work, under strict dust and inhalation controls", "weakest_at": "Low conductivity in sputtered films (7.2 to 9.09 S/cm) and a carcinogen hazard (H350, with IARC Group 1 for nickel compounds)", "identity": { "formula": "NiO", "cas": "1313-99-1", "crystal_system": "cubic", "space_group": "Fm3m", "designations": [], "source": "vidal-2005-nio", "where": "Experimental Procedures, paragraph beginning 'No antiferromagnetic distortion' (face-centred cubic, Fm3m, lattice constant 4.169(2) Å at 298 K); CAS number in Section 3 of sigma-sds-nio" }, "tags": { "environments": [], "stresses": [ "extreme-heat" ], "applications": [ "electronics-and-chips", "batteries", "propulsion-and-tanks" ] }, "properties": [ { "benchmark": "density", "label": "Relative density, nickel(II) oxide (Sigma-Aldrich SDS)", "value": 6.67, "bound": "exact", "unit": "g/cm3", "scope": "material", "conditions": { "temperature": "25 °C (77 °F)", "grade": "powder, Sigma-Aldrich product 637130" }, "method": "Value printed in a supplier safety data sheet as relative density", "status": "ground", "source": "sigma-sds-nio", "where": "Section 9 (Physical and Chemical Properties), item m) Relative density", "source_detail": { "title": "Sigma-Aldrich safety data sheet, nickel(II) oxide, product 637130 (Version 4.10, revision 28 February 2015)", "id": "CAS 1313-99-1, product 637130", "url": "https://www.nanofab.utah.edu/wp-content/uploads/2018/08/NickelII-oxide-Sigma-Aldrich-28Feb15_v4.1.pdf", "year": 2015, "kind": "datasheet", "license": "supplier document, linked not reproduced" } }, { "benchmark": "density", "label": "Density, nickel oxide (Angstrom Sciences SDS)", "value": 6.67, "bound": "exact", "unit": "g/cm3", "scope": "material", "conditions": { "grade": "powder, sputtering target and custom parts, as listed in the SDS" }, "method": "Value printed in a supplier safety data sheet", "status": "ground", "source": "angstrom-sds-nio", "where": "Section 9 (Physical and Chemical Properties), Density row (printed as 6.67 g/cc)", "source_detail": { "title": "Angstrom Sciences safety data sheet, Nickel Oxide (last revision 07/02/15)", "id": "CAS 1313-99-1, EC 215-215-7", "url": "https://angstromsciences.com/wp-content/uploads/files/SDS/Nickel%20Oxide.pdf", "year": 2015, "kind": "datasheet", "license": "supplier document, linked not reproduced" } }, { "benchmark": "melting_point", "label": "Melting point, nickel oxide (Angstrom Sciences SDS)", "value": 1984, "bound": "exact", "unit": "°C", "scope": "material", "conditions": { "grade": "powder, as listed in the SDS" }, "method": "Value printed in a supplier safety data sheet", "status": "ground", "note": "The Sigma-Aldrich SDS for the same compound gives melting point as No data available, so this value rests on one reseller sheet.", "source": "angstrom-sds-nio", "where": "Section 9 (Physical and Chemical Properties), Melting Point row", "source_detail": { "title": "Angstrom Sciences safety data sheet, Nickel Oxide (last revision 07/02/15)", "id": "CAS 1313-99-1, EC 215-215-7", "url": "https://angstromsciences.com/wp-content/uploads/files/SDS/Nickel%20Oxide.pdf", "year": 2015, "kind": "datasheet", "license": "supplier document, linked not reproduced" } }, { "benchmark": "molar_mass", "label": "Molecular weight, nickel oxide (computed)", "value": 74.693, "bound": "exact", "unit": "g/mol", "scope": "material", "conditions": { "basis": "computed property in the database record" }, "method": "Computed molecular weight printed in the PubChem record", "status": "calculated", "source": "pubchem-nio", "where": "Chemical and Physical Properties, Computed Properties, Molecular Weight", "source_detail": { "title": "PubChem compound record, CID 14805 (formula NiO, CAS 1313-99-1; record title reads Nickel trioxide)", "id": "CID 14805", "url": "https://pubchem.ncbi.nlm.nih.gov/rest/pug_view/data/compound/14805/JSON", "year": 2026, "kind": "database", "license": "public domain (NCBI)" } }, { "benchmark": "water_solubility", "label": "Water solubility, nickel oxide at 20 °C", "value": 0.00003, "bound": "exact", "unit": "g/l", "scope": "material", "conditions": { "temperature": "20 °C (68 °F)" }, "method": "OECD Test Guideline 105, as printed in the supplier safety data sheet", "status": "ground", "note": "The SDS describes the product as practically insoluble.", "source": "sigma-sds-nio", "where": "Section 9, item n) Water solubility", "source_detail": { "title": "Sigma-Aldrich safety data sheet, nickel(II) oxide, product 637130 (Version 4.10, revision 28 February 2015)", "id": "CAS 1313-99-1, product 637130", "url": "https://www.nanofab.utah.edu/wp-content/uploads/2018/08/NickelII-oxide-Sigma-Aldrich-28Feb15_v4.1.pdf", "year": 2015, "kind": "datasheet", "license": "supplier document, linked not reproduced" } }, { "benchmark": "band_gap", "label": "Optical band gap, single-crystal NiO (range)", "value": 3.6, "value_high": 4, "bound": "range", "unit": "eV", "scope": "material", "conditions": { "crystal": "single crystal", "temperature": "not stated in the review" }, "method": "Range stated in a 2024 review of p-type transparent conducting oxides", "status": "ground", "source": "arxiv-ptco-2024", "where": "Section on NiO, sentence beginning 'However, the optical band energy of single-crystal NiO', citing reference [5] of the review", "source_detail": { "title": "Progress in Developing Highly Efficient p-Type TCOs for Transparent Electronics: A Comprehensive Review (Singh and Bhardwaj)", "id": "arXiv 2405.14354", "url": "https://arxiv.org/pdf/2405.14354", "year": 2024, "kind": "paper", "license": "arXiv preprint (cited, not reproduced)" } }, { "benchmark": "band_gap", "label": "Optical band gap, 110 nm sputtered NiO film on glass", "value": 3.8, "bound": "exact", "unit": "eV", "scope": "material", "conditions": { "film_thickness": "110 nm", "substrate": "glass", "deposition": "magnetron sputtering" }, "method": "Value tabulated in a 2024 review (Table 4) from the study it cites as reference [5]", "status": "ground", "source": "arxiv-ptco-2024", "where": "Table 4 (Binary oxide materials as p-type TCO), NiO row, magnetron sputtering", "source_detail": { "title": "Progress in Developing Highly Efficient p-Type TCOs for Transparent Electronics: A Comprehensive Review (Singh and Bhardwaj)", "id": "arXiv 2405.14354", "url": "https://arxiv.org/pdf/2405.14354", "year": 2024, "kind": "paper", "license": "arXiv preprint (cited, not reproduced)" } }, { "benchmark": "electrical_conductivity", "label": "Electrical conductivity, 110 nm sputtered NiO film", "value": 7.2, "bound": "exact", "unit": "S/cm", "scope": "material", "conditions": { "film_thickness": "110 nm", "substrate": "glass", "deposition": "magnetron sputtering" }, "method": "Value tabulated in a 2024 review (Table 4)", "status": "ground", "source": "arxiv-ptco-2024", "where": "Table 4, NiO row, electrical conductivity column (S/cm)", "source_detail": { "title": "Progress in Developing Highly Efficient p-Type TCOs for Transparent Electronics: A Comprehensive Review (Singh and Bhardwaj)", "id": "arXiv 2405.14354", "url": "https://arxiv.org/pdf/2405.14354", "year": 2024, "kind": "paper", "license": "arXiv preprint (cited, not reproduced)" } }, { "benchmark": "optical_transmittance", "label": "Average transmittance, 110 nm sputtered NiO film", "value": 40, "bound": "exact", "unit": "%", "scope": "material", "conditions": { "film_thickness": "110 nm", "substrate": "glass", "deposition": "magnetron sputtering" }, "method": "Value tabulated in a 2024 review (Table 4)", "status": "ground", "source": "arxiv-ptco-2024", "where": "Table 4, NiO row, average transmittance column", "source_detail": { "title": "Progress in Developing Highly Efficient p-Type TCOs for Transparent Electronics: A Comprehensive Review (Singh and Bhardwaj)", "id": "arXiv 2405.14354", "url": "https://arxiv.org/pdf/2405.14354", "year": 2024, "kind": "paper", "license": "arXiv preprint (cited, not reproduced)" } }, { "benchmark": "electrical_conductivity", "label": "Electrical conductivity, 100 nm RF-sputtered NiO film", "value": 9.09, "bound": "exact", "unit": "S/cm", "scope": "material", "conditions": { "film_thickness": "100 nm", "substrate": "glass", "deposition": "RF magnetron sputtering" }, "method": "Value tabulated in a 2024 review (Table 4)", "status": "ground", "source": "arxiv-ptco-2024", "where": "Table 4, NiO RFMS row (reference [96]), electrical conductivity column", "source_detail": { "title": "Progress in Developing Highly Efficient p-Type TCOs for Transparent Electronics: A Comprehensive Review (Singh and Bhardwaj)", "id": "arXiv 2405.14354", "url": "https://arxiv.org/pdf/2405.14354", "year": 2024, "kind": "paper", "license": "arXiv preprint (cited, not reproduced)" } }, { "benchmark": "optical_transmittance", "label": "Average transmittance, 100 nm RF-sputtered NiO film", "value": 69, "bound": "exact", "unit": "%", "scope": "material", "conditions": { "film_thickness": "100 nm", "substrate": "glass", "deposition": "RF magnetron sputtering" }, "method": "Value tabulated in a 2024 review (Table 4)", "status": "ground", "source": "arxiv-ptco-2024", "where": "Table 4, NiO RFMS row (reference [96]), average transmittance column", "source_detail": { "title": "Progress in Developing Highly Efficient p-Type TCOs for Transparent Electronics: A Comprehensive Review (Singh and Bhardwaj)", "id": "arXiv 2405.14354", "url": "https://arxiv.org/pdf/2405.14354", "year": 2024, "kind": "paper", "license": "arXiv preprint (cited, not reproduced)" } }, { "benchmark": "hall_mobility", "label": "Hall mobility, 100 nm RF-sputtered NiO film", "value": 6.12, "bound": "exact", "unit": "cm2/V-s", "scope": "material", "conditions": { "film_thickness": "100 nm", "substrate": "glass", "deposition": "RF magnetron sputtering" }, "method": "Value tabulated in a 2024 review (Table 4)", "status": "ground", "source": "arxiv-ptco-2024", "where": "Table 4, NiO RFMS row (reference [96]), Hall mobility column", "source_detail": { "title": "Progress in Developing Highly Efficient p-Type TCOs for Transparent Electronics: A Comprehensive Review (Singh and Bhardwaj)", "id": "arXiv 2405.14354", "url": "https://arxiv.org/pdf/2405.14354", "year": 2024, "kind": "paper", "license": "arXiv preprint (cited, not reproduced)" } }, { "benchmark": "lattice_constant_a", "label": "Lattice constant a, NiO single crystal at 298 K", "value": 4.169, "bound": "exact", "unit": "Å", "scope": "material", "conditions": { "crystal": "single crystal, face-centred cubic (Fm3m)", "temperature": "298 K" }, "method": "Least-squares refinement of X-ray diffraction data, printed as 4.169(2) Å", "status": "ground", "note": "The paper prints the uncertainty as (2) in the last digit.", "source": "vidal-2005-nio", "where": "Experimental Procedures, paragraph after the structure factor table, sentence beginning 'Least-squares refinement'", "source_detail": { "title": "Indications of the Magnetic State in the Charge Distributions of MnO, CoO, and NiO. III: Antiferromagnetism of NiO (Vidal, Vidal-Valat and Kurki-Suonio; Crystallography Reports, vol. 50, no. 1, 2005)", "id": "Crystallography Reports 50(1), pp. 20 to 26", "url": "https://www.mv.helsinki.fi/home/kurkisuo/6.1.A/05-NiO.pdf", "year": 2005, "kind": "paper", "license": "not stated on the copy read" } } ], "corrosion": [ { "environment": "Nickel heated in dry oxygen at 1000 °C (NiO scale on nickel)", "headline": "The NiO scale grows outward and pushes sideways with a stress of about 10 MN/m2, so it is not a passive layer.", "effect": "The NASA report says nickel oxide growing on nickel in oxygen at 1000 °C has a mean grain-boundary pressure of approximately 10 MN/m2, and that the scale is not passive because it generates a lateral compressive stress during oxidation. The scale thickens almost exclusively by outward diffusion of metal ions through the oxide.", "rating": "moderate", "conditions": { "temperature": "1000 °C", "atmosphere": "oxygen", "substrate": "nickel (Nickel-201 and Nickel-270 in the report)" }, "source": "nasa-tn-d5266", "where": "Section 'Case 2: The active surface layer' (page 8), and the introduction, point (3)" }, { "environment": "Ni/NiO-YSZ composites in a solid oxide fuel cell anode, through burnout and redox cycling", "headline": "Nickel expands when it oxidises, so the anode composition has to stay within a window that also avoids thermal mismatch with the electrolyte.", "effect": "The Waterloo thesis abstract says the composites made from nickel metal expand due to nickel oxidation during burnout, while the composites that started from NiO change little in volume on reduction when YSZ is present. It limits nickel loading to a window with a minimum for electrical conductivity and a maximum to avoid thermal mismatch with YSZ.", "rating": "moderate", "conditions": { "nickel_loading": "4 to 77 vol% of total solids (range studied)", "process": "burnout and reduction of porous composites" }, "source": "clemmer-2006-nio-ysz", "where": "Abstract" }, { "environment": "Water (practically insoluble)", "headline": "The supplier SDS shows negligible dissolution in water, but gives no corrosion rate.", "effect": "The Sigma-Aldrich SDS gives a water solubility of 0.00003 g/l at 20 °C and describes the product as practically insoluble. The SDS gives no corrosion rate, so the rating is unknown.", "rating": "unknown", "conditions": { "temperature": "20 °C" }, "source": "sigma-sds-nio", "where": "Section 9, item n) Water solubility" } ], "risks": { "hazards": [ { "text": "The Sigma-Aldrich SDS classes nickel(II) oxide as Danger with H317 (allergic skin reaction), H350 (may cause cancer), H372 (organ damage through prolonged or repeated exposure) and H413 (long-lasting harm to aquatic life).", "ghs": [ "H317", "H350", "H372", "H413" ], "source": "sigma-sds-nio", "where": "Section 2 (Hazards identification), GHS classification" }, { "text": "PubChem's summary of ECHA notifications gives the same four codes, with H317 in 100 percent of classifying notifications and H350 in 98.9 percent. The record title reads Nickel trioxide, but the formula NiO and CAS 1313-99-1 match nickel(II) oxide.", "ghs": [ "H317", "H350", "H372", "H413" ], "source": "pubchem-nio", "where": "Safety and Hazards, GHS Classification, ECHA C&L Notifications Summary" }, { "text": "A Solaronix SDS for a nickel oxide paste (Ni-Nanoxide N/SP, nickel monoxide 10 to 25 percent) classes it as Danger with H315, H317, H350i (cancer by inhalation), H372 and H413. It is a paste, so this is a product classification and not a pure NiO classification.", "ghs": [ "H315", "H317", "H350i", "H372", "H413" ], "source": "solaronix-sds-nio", "where": "Sections 2 and 3 (dangerous components)" }, { "text": "IARC classifies nickel compounds in Group 1, carcinogenic to humans, with a definite link to lung, nasal and paranasal cancer. The CAREX Canada profile says the evaluation was mainly for nickel compounds containing oxygen and sulphur. The page does not name nickel oxide directly.", "ghs": [], "source": "carex-nickel", "where": "Nickel Profile, paragraph on IARC Monograph Vol. 100C (2012)" } ], "failure_risks": [ { "mode": "Growth stress in a NiO scale on nickel at high temperature", "trigger": "Heating nickel in oxygen at about 1000 °C for long periods", "consequence": "The scale carries a compressive grain-boundary stress of about 10 MN/m2, which the NASA report models as a change to the high-temperature creep behaviour of the nickel beneath it.", "severity": "moderate", "source": "nasa-tn-d5266", "where": "Section 'Case 2: The active surface layer' (page 8)" }, { "mode": "Volume change of nickel in a fuel cell anode on redox cycling", "trigger": "Oxidation of the nickel phase during burnout or a loss of reducing gas in service", "consequence": "Expansion of the nickel phase can break the match with the YSZ electrolyte, so the nickel loading has to stay inside a narrow window.", "severity": "moderate", "source": "clemmer-2006-nio-ysz", "where": "Abstract" } ], "side_effects": [], "handling": [ { "text": "Avoid contact with skin and eyes and avoid forming dust. Provide exhaust ventilation where dust is formed. Combustible dust can form in further processing.", "source": "sigma-sds-nio", "where": "Section 7.1 (Precautions for safe handling)" }, { "text": "Handle and store under inert gas, in a dry place.", "source": "sigma-sds-nio", "where": "Section 7.2 (Conditions for safe storage)" }, { "text": "Pick up spills without creating dust, sweep up or shovel, and keep the waste in closed containers.", "source": "sigma-sds-nio", "where": "Section 6 (Accidental release measures)" } ], "mitigations": [ { "text": "Workplace limits in the SDS: OSHA PEL 1 mg/m3 TWA, NIOSH REL 0.015 mg/m3 TWA (potential occupational carcinogen), ACGIH TLV 0.2 mg/m3 TWA (confirmed human carcinogen, lung cancer).", "source": "sigma-sds-nio", "where": "Section 8.1 (Control parameters)" }, { "text": "NIOSH lists the IDLH for nickel metal and other compounds as 10 mg/m3 as Ni. The NIOSH entry does not state the basis for this value on the page read.", "source": "niosh-npg-nickel", "where": "IDLH heading of the NIOSH Pocket Guide entry" }, { "text": "Where a risk assessment shows that respirators are needed, the SDS recommends a full-face particle respirator (N100 or P3 cartridges) as a backup to engineering controls.", "source": "sigma-sds-nio", "where": "Section 8.2 (Exposure controls), respiratory protection" } ] }, "uses": [ { "application": "electronics-and-chips", "device": "p-type transparent conducting layer in transparent p-n junctions and thin-film transistors", "example": "The 2024 review calls NiO the first p-type transparent conducting oxide. Sputtered NiO films in its Table 4 reach 7.2 S/cm with 40 percent transmittance (110 nm) and 9.09 S/cm with 69 percent transmittance (100 nm, RF sputtering).", "source": "arxiv-ptco-2024", "where": "Introduction and NiO discussion; Table 4, NiO rows" }, { "application": "batteries", "device": "Solid oxide fuel cell anode made from porous Ni/YSZ or NiO/YSZ composites", "example": "A 2006 Waterloo thesis studied porous Ni/YSZ and NiO/YSZ composites for solid oxide fuel cells, with nickel loadings from 4 to 77 vol%. The abstract reports that nickel-metal composites expand on oxidation during burnout.", "source": "clemmer-2006-nio-ysz", "where": "Abstract" }, { "application": "propulsion-and-tanks", "device": "Oxide scale on nickel and nickel-base alloys in hot oxidising gas", "example": "A NASA report on oxidation of nickel at 1000 °C models the growing NiO scale and says the results should carry over to complex nickel-base alloy systems. This is a stated expectation, not a measured alloy result.", "source": "nasa-tn-d5266", "where": "Introduction, point (4)" } ], "supply": [ { "subject": "Nickel (feedstock for NiO)", "producers": [ { "country": "Indonesia", "share_percent": 66.7, "year": 2025 }, { "country": "Philippines", "share_percent": 6.9, "year": 2025 }, { "country": "Russia", "share_percent": 5.1, "year": 2025 }, { "country": "New Caledonia", "share_percent": 3.6, "year": 2025 }, { "country": "Canada", "share_percent": 3.6, "year": 2025 }, { "country": "China", "share_percent": 3.1, "year": 2025 }, { "country": "Brazil", "share_percent": 1.8, "year": 2025 }, { "country": "Australia", "share_percent": 1.2, "year": 2025 }, { "country": "United States", "share_percent": 0.3, "year": 2025 } ], "critical_lists": [ { "list": "USGS 2025 List of Critical Minerals (nickel is on the final list, used to make high-strength steel and rechargeable batteries)", "listed": true } ], "recycling": "USGS: nickel recovered from scrap was about 60 percent of US apparent consumption in 2025, mostly from stainless-steel scrap.", "substitutes": [ "USGS nickel chapter: low-nickel, duplex or ultrahigh-chromium stainless steels can replace austenitic grades, and titanium alloys can replace nickel-base alloys in corrosive environments." ], "source": "usgs-mcs2026-nickel", "where": "World Mine Production and Reserves table, 2025e column (world total 3,900,000 t, rounded); Recycling; Substitutes. The producer shares are calculated by Space Mushroom from each tonnage divided by the 3,900,000 t world total, not printed by USGS. USGS gives no NiO production table." } ], "media": [], "documents": [ { "title": "Sigma-Aldrich safety data sheet, nickel(II) oxide, product 637130 (Version 4.10, revision 28 February 2015; copy hosted by Utah NanoFab)", "type": "sds", "url": "https://www.nanofab.utah.edu/wp-content/uploads/2018/08/NickelII-oxide-Sigma-Aldrich-28Feb15_v4.1.pdf", "year": 2015 }, { "title": "Angstrom Sciences safety data sheet, Nickel Oxide (CAS 1313-99-1; last revision 07/02/15)", "type": "sds", "url": "https://angstromsciences.com/wp-content/uploads/files/SDS/Nickel%20Oxide.pdf", "year": 2015 }, { "title": "Solaronix safety data sheet, Ni-Nanoxide N/SP (nickel oxide paste, EU CLP format; printed 25.06.2013)", "type": "sds", "url": "https://www.solaronix.com/msds/MSDS_Ni-Nanoxide_N__SP.pdf", "year": 2013 }, { "title": "PubChem compound record, CID 14805 (formula NiO, CAS 1313-99-1)", "type": "database", "url": "https://pubchem.ncbi.nlm.nih.gov/compound/14805", "year": 2026 }, { "title": "Progress in Developing Highly Efficient p-Type TCOs for Transparent Electronics: A Comprehensive Review (arXiv 2405.14354)", "type": "paper", "url": "https://arxiv.org/pdf/2405.14354", "year": 2024 }, { "title": "Indications of the Magnetic State in the Charge Distributions of MnO, CoO, and NiO. III: Antiferromagnetism of NiO (Crystallography Reports, 2005)", "type": "paper", "url": "https://www.mv.helsinki.fi/home/kurkisuo/6.1.A/05-NiO.pdf", "year": 2005 }, { "title": "A Proposed Model for the Effect of Oxidation on the High-Temperature Deformation of Nickel (NASA TN D-5266)", "type": "report", "url": "https://ntrs.nasa.gov/api/citations/19690017683/downloads/19690017683.pdf", "year": 1969 }, { "title": "The Processing and Characterization of Porous Ni/YSZ and NiO/YSZ Composites used in Solid Oxide Fuel Cell Applications (University of Waterloo, 2006)", "type": "paper", "url": "https://uwspace.uwaterloo.ca/handle/10012/2883", "year": 2006 }, { "title": "CAREX Canada, Nickel profile (IARC Monograph Vol. 100C classification)", "type": "report", "url": "https://www.carexcanada.ca/?p=9614", "year": 2026 }, { "title": "USGS Mineral Commodity Summaries 2026: Nickel", "type": "report", "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-nickel.pdf", "year": 2026 }, { "title": "NIOSH Pocket Guide, Nickel metal and other compounds (as Ni)", "type": "report", "url": "https://www.cdc.gov/niosh/npg/npgd0445.html", "year": 2026 } ], "gaps": [ "No battery-precursor source for NiO was read. The open-access 2022 review (Entwistle et al., Energy Reports) and the 2025 review describe hydroxide precursors milled with a lithium salt. A patent snippet says NiO forms as an intermediate when Ni(OH)2 is heated at 500 °C, but the patent was not fetched, so the battery-precursor use is not stated as a source-backed use.", "The protective Cr2O3 scale and the spallation behaviour of NiO on Ni-Cr and Ni-Mo-Cr alloys were seen only in search snippets. No open alloy-oxidation source was opened, so the alloy claim is limited to the NASA statement that its results should apply to nickel-base alloys.", "Bulk thermal expansion coefficient, thermal conductivity and the Néel temperature were not read in a fetched source in this run. The Néel temperature of 523 K appeared only in a search snippet.", "Molar volume and the NiO/Ni volume change on reduction were in a 2011 MDPI review that returned HTTP 403, so they are not used.", "The IARC Volume 100C monograph was not opened. The Group 1 statement rests on the CAREX Canada profile. The CAREX page does not name nickel oxide directly.", "Atomic weights for nickel and oxygen were not read in a source opened for this profile, so the recipe parts carry no atomic_weight.", "Acid and base attack rates were not found in a source read in this run.", "The PubChem record CID 14805 has the title Nickel trioxide while the formula and CAS number match nickel(II) oxide; PubChem's own melting point and density were not used because the experimental-properties page returned a verification screen.", "Electrical conductivity, band gap, water solubility, molar mass, Hall mobility and lattice constant are not in property-canon.yaml; snake_case names were used, as in zinc-oxide.yaml.", "The H350 (Sigma-Aldrich, PubChem) and H350i (Solaronix paste) classifications differ; both are kept with their source.", "The melting point of 1984 °C comes from one reseller SDS; the Sigma-Aldrich SDS gives no melting point.", "The NASA Tech Brief on black nickel plating (1974) describes a nickel plating process, not NiO, and was not used.", "No flight, vacuum or space-exposure result for NiO was found in the sources read.", "The EU critical raw materials list was not checked for nickel. Crustal abundance of nickel was not read." ], "story": { "why": "Nickel oxide is a simple rock-salt oxide and the p-type counterpart to n-type transparent oxides such as zinc oxide. Its record in the sources read is in three places: sputtered films that conduct as p-type layers (7.2 and 9.09 S/cm, with 40 to 69 percent transmittance), porous Ni/YSZ and NiO/YSZ composites studied as solid oxide fuel cell anodes, and a NiO scale on nickel that builds a compressive stress of about 10 MN/m2 at 1000 °C. Its weak point is the hazard: the SDS classes it as a carcinogen and IARC places nickel compounds in Group 1. No flight or space-exposure data for NiO was found.", "uses": [ { "where": "Transparent p-type layers", "line": "The 2024 review calls NiO the first p-type transparent conducting oxide. It is mostly used in transparent p-n junctions and thin-film transistors." }, { "where": "Solid oxide fuel cell anodes", "line": "A 2006 Waterloo thesis studied porous Ni/YSZ and NiO/YSZ composites with nickel loadings from 4 to 77 vol%, and found the nickel loading must stay in a window to keep conductivity and avoid thermal mismatch with the electrolyte." }, { "where": "Oxide scale on nickel and nickel alloys", "line": "A NiO scale on nickel at 1000 °C in oxygen carries a compressive stress of about 10 MN/m2. The NASA report expects its results to apply to nickel-base alloys." } ], "can_do": [ { "label": "p-type conduction", "line": "A 110 nm sputtered NiO film on glass conducts at 7.2 S/cm with 40 percent average transmittance.", "scope": "material", "value": "7.2 S/cm at 110 nm" }, { "label": "Higher conductivity film", "line": "An RF-sputtered 100 nm NiO film reached 9.09 S/cm, 69 percent transmittance and 6.12 cm2/V-s Hall mobility.", "scope": "material", "value": "9.09 S/cm at 100 nm" }, { "label": "Crystal cell", "line": "The rock-salt cell has a lattice constant of 4.169 Å at 298 K from X-ray refinement.", "scope": "material", "value": "4.169 Å cubic lattice" }, { "label": "Scale stress", "line": "Nickel oxide grown on nickel in oxygen at 1000 °C carries a grain-boundary pressure of about 10 MN/m2.", "scope": "material", "value": "about 10 MN/m2 at 1000 °C" } ], "compare": "Compared with zinc oxide, nickel oxide melts at a higher temperature and is denser, as the compare rows show. Its sputtered-film conductivity (7.2 to 9.09 S/cm) is for an undoped p-type film, so it is not directly comparable with the doped n-type zinc oxide films. The main difference is the hazard: zinc oxide is classed only as an aquatic hazard in its SDS, while nickel oxide carries a carcinogen classification.", "compare_rows": [ { "label": "Melting point", "benchmark": "melting_point", "scope": "material" }, { "label": "Density", "benchmark": "density", "scope": "material" }, { "label": "Band gap", "benchmark": "band_gap", "scope": "material" } ], "handling": [ "Avoid dust and use exhaust ventilation.", "Handle and store under inert gas in a dry place.", "Treat it as a carcinogen and keep exposure within the OSHA, NIOSH and ACGIH limits printed in the SDS." ], "good_for": [ "Undoped p-type transparent layers in research devices, at 7.2 to 9.09 S/cm in sputtered films.", "Nickel-based solid oxide fuel cell anode work, where the NiO/YSZ composite is the starting material.", "Studying oxide scale growth on nickel at high temperature, where the scale stress is about 10 MN/m2 at 1000 °C." ], "watch_out": [ "The carcinogen classification: H350 in the Sigma-Aldrich SDS, H350i in the paste SDS, and IARC Group 1 for nickel compounds.", "Volume change of nickel on oxidation in anodes, and the scale growth stress on nickel.", "Hazard classes differ between the SDS sheets read, and the PubChem summary is mixed." ], "verdict": "Nickel oxide is a simple, well-characterised p-type oxide, with film conductivity of about 7 to 9 S/cm in the sources read. Its carcinogen classification and dust hazard make it a controlled material. It has no flight record, and the battery-precursor use is not backed by a source read in this run, so it is listed as a gap.", "recipe": { "line": "NiO is a 1:1 compound of nickel and oxygen. It crystallises in the face-centred cubic rock-salt structure (space group Fm3m), with a lattice constant of 4.169 Å at 298 K. Simple rock-salt structure is one reason the 2024 review gives for its use as a p-type transparent conductor.", "parts": [ { "name": "Nickel", "symbol": "Ni", "role": "The metal cation. Ni(II) ions sit in the rock-salt lattice with oxygen as the counter-ion." }, { "name": "Oxygen", "symbol": "O", "role": "The anion. Oxygen forms the other half of the rock-salt lattice with nickel." } ] }, "risk_groups": [ { "title": "For people", "lead": "The supplier safety data sheets classify nickel oxide as a Danger-level carcinogen and skin sensitiser. IARC places nickel compounds in Group 1.", "points": [ { "label": "Inhalation", "line": "The Sigma-Aldrich SDS gives H350 (may cause cancer) and H372 (organ damage from repeated exposure). The paste SDS gives H350i (cancer by inhalation)." }, { "label": "Dust limits", "line": "OSHA PEL 1 mg/m3, NIOSH REL 0.015 mg/m3 (potential carcinogen), and ACGIH TLV 0.2 mg/m3 are the workplace limits printed in the SDS." }, { "label": "Skin", "line": "H317 means it can cause an allergic skin reaction." } ], "level": 1, "verdict": "Cancer risk by inhalation; skin sensitiser" }, { "title": "If the oxide is heated or cycled", "lead": "High-temperature oxidation and redox cycling change the stress and the volume of nickel-based parts.", "points": [ { "label": "Scale stress", "line": "On nickel at 1000 °C in oxygen, the NiO scale carries a compressive stress of about 10 MN/m2." }, { "label": "Anode cycling", "line": "In Ni/YSZ composites, nickel expands when it oxidises, so the nickel loading has to stay in a window." } ] }, { "title": "Handling and storage", "points": [ { "label": "Dust", "line": "Avoid dust formation and provide exhaust ventilation. Clean up spills without creating dust." }, { "label": "Storage", "line": "Handle and store under inert gas, in a dry place, as the Sigma-Aldrich SDS says." } ] } ] }, "updated": "2026-10-26", "review": { "status": "draft", "method": "assistant", "checked_values": 13, "unreachable": 4, "caveats": 6, "note": "Read by an AI assistant on 2026-10-26 from the pages and PDFs fetched in that run. Two MDPI papers (the SOFC redox review and the p-type Ni1-xO film paper) returned HTTP 403, and the IARC Volume 100C PDF did not download. The PubChem experimental-properties page returned a verification screen. The Solaronix SDS is for a paste, not pure NiO. The melting point comes from one reseller SDS. Caveats: the Membranes review and the Coatings paper are not used; the battery-precursor use is not sourced; the alloy-scale statements rest on the NASA report and a search snippet only." }, "sources": { "pubchem-nio": { "title": "PubChem compound record, CID 14805 (formula NiO, CAS 1313-99-1; record title reads Nickel trioxide)", "id": "CID 14805", "url": "https://pubchem.ncbi.nlm.nih.gov/rest/pug_view/data/compound/14805/JSON", "year": 2026, "kind": "database", "license": "public domain (NCBI)" }, "sigma-sds-nio": { "title": "Sigma-Aldrich safety data sheet, nickel(II) oxide, product 637130 (Version 4.10, revision 28 February 2015)", "id": "CAS 1313-99-1, product 637130", "url": "https://www.nanofab.utah.edu/wp-content/uploads/2018/08/NickelII-oxide-Sigma-Aldrich-28Feb15_v4.1.pdf", "year": 2015, "kind": "datasheet", "license": "supplier document, linked not reproduced" }, "angstrom-sds-nio": { "title": "Angstrom Sciences safety data sheet, Nickel Oxide (last revision 07/02/15)", "id": "CAS 1313-99-1, EC 215-215-7", "url": "https://angstromsciences.com/wp-content/uploads/files/SDS/Nickel%20Oxide.pdf", "year": 2015, "kind": "datasheet", "license": "supplier document, linked not reproduced" }, "solaronix-sds-nio": { "title": "Solaronix safety data sheet, Ni-Nanoxide N/SP (nickel oxide paste)", "id": "printed 25.06.2013, version 1", "url": "https://www.solaronix.com/msds/MSDS_Ni-Nanoxide_N__SP.pdf", "year": 2013, "kind": "datasheet", "license": "supplier document, linked not reproduced" }, "arxiv-ptco-2024": { "title": "Progress in Developing Highly Efficient p-Type TCOs for Transparent Electronics: A Comprehensive Review (Singh and Bhardwaj)", "id": "arXiv 2405.14354", "url": "https://arxiv.org/pdf/2405.14354", "year": 2024, "kind": "paper", "license": "arXiv preprint (cited, not reproduced)" }, "vidal-2005-nio": { "title": "Indications of the Magnetic State in the Charge Distributions of MnO, CoO, and NiO. III: Antiferromagnetism of NiO (Vidal, Vidal-Valat and Kurki-Suonio; Crystallography Reports, vol. 50, no. 1, 2005)", "id": "Crystallography Reports 50(1), pp. 20 to 26", "url": "https://www.mv.helsinki.fi/home/kurkisuo/6.1.A/05-NiO.pdf", "year": 2005, "kind": "paper", "license": "not stated on the copy read" }, "nasa-tn-d5266": { "title": "A Proposed Model for the Effect of Oxidation on the High-Temperature Deformation of Nickel (James S. Wolf, NASA TN D-5266, Lewis Research Center)", "id": "NTRS 19690017683", "url": "https://ntrs.nasa.gov/api/citations/19690017683/downloads/19690017683.pdf", "year": 1969, "kind": "report", "license": "public domain (NASA)" }, "clemmer-2006-nio-ysz": { "title": "The Processing and Characterization of Porous Ni/YSZ and NiO/YSZ Composites used in Solid Oxide Fuel Cell Applications (Ryan Clemmer, University of Waterloo)", "id": "UWSpace handle 10012/2883", "url": "https://uwspace.uwaterloo.ca/handle/10012/2883", "year": 2006, "kind": "paper", "license": "not stated on the repository page" }, "carex-nickel": { "title": "CAREX Canada, Nickel profile", "id": "CAREX Canada nickel profile", "url": "https://www.carexcanada.ca/?p=9614", "year": 2026, "kind": "web", "license": "not stated" }, "usgs-mcs2026-nickel": { "title": "Mineral Commodity Summaries 2026, Nickel", "id": "USGS MCS 2026", "url": "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-nickel.pdf", "year": 2026, "kind": "report", "license": "public domain (USGS)" }, "usgs-crit2025": { "title": "About the 2025 List of Critical Minerals (USGS, final list of 60 minerals)", "id": "Final 2025 List of Critical Minerals", "url": "https://www.usgs.gov/programs/mineral-resources-program/science/about-2025-list-critical-minerals", "year": 2025, "kind": "web", "license": "public domain (USGS)" }, "niosh-npg-nickel": { "title": "NIOSH Pocket Guide to Chemical Hazards, Nickel metal and other compounds (as Ni)", "id": "NIOSH NPG entry npgd0445; CAS 7440-02-0 (metal)", "url": "https://www.cdc.gov/niosh/npg/npgd0445.html", "year": 2026, "kind": "handbook", "license": "public domain (CDC)" } }, "license": "CC-BY-4.0", "url": "https://spacemushroom.com/profiles/nickel-oxide/" }