Gallium nitride GaN

spore: profile
id: gallium-nitride
spore_version: 0.2
family: semiconductor-materials
name: Gallium nitride
abbreviation: GaN
role: wide-bandgap semiconductor
category: semiconductors
type: gan
summary: >
  GaN is a wide-bandgap III-V semiconductor with a wurtzite crystal structure. The Ioffe archive gives a band gap of 3.39 eV at 300 K and an approximate breakdown field of 5 x 10^6 V/cm. Its electron mobility is modest, at most 440 cm2/(V s) in the purest material at 300 K. NASA tested EPC1001 GaN transistors on the ground: after heavy-ion irradiation and 1000 thermal cycles between -55 and +125 degC, all eight parts stayed functional.
best_for: "High-voltage and high-frequency power switching, and radiation-tolerant electronics where a wide band gap and high breakdown field matter (NASA ground tests of GaN transistors)"
weakest_at: "Modest electron mobility compared with the best III-V materials, and the cost and limited supply of gallium"
identity:
  formula: GaN
  cas: "25617-97-4"
  crystal_system: hexagonal (wurtzite)
  space_group: "P6_3mc"
  source: ioffe-basic
  where: "Basic Parameters for Wurtzite crystal structure: Crystal structure and Group of symmetry rows (C 4 6v, P6 3 mc); CAS number from PubChem CID 117559"
tags:
  environments: []
  stresses: [radiation, thermal-cycling]
  applications: [electronics-and-chips]
properties:
  - benchmark: density
    value: 6.15
    unit: g/cm3
    scope: material
    conditions: {structure: wurtzite, temperature: "300 K"}
    method: Tabulated value as printed in the Ioffe basic parameters table for wurtzite GaN
    status: ground
    source: ioffe-basic
    where: "Basic Parameters for Wurtzite crystal structure, Density row"
  - benchmark: melting_point
    value: 2500
    unit: degC
    scope: material
    conditions: {basis: "melting point as printed; the same table points to the equilibrium N2 pressure over GaN (Porowski 1997)"}
    method: Tabulated value in the Ioffe basic parameters table, cited to Bougrov et al. (2001) and Porowski (1997)
    status: ground
    source: ioffe-thermal
    where: "Basic parameters table, Melting point T_m row"
  - benchmark: specific_heat
    value: 0.49
    unit: J g-1 degC-1
    scope: material
    conditions: {temperature: "not printed in the table row"}
    method: Tabulated value as printed; attributed to Bougrov et al. (2001)
    status: ground
    source: ioffe-thermal
    where: "Basic parameters table, Specific heat row"
  - benchmark: bulk_modulus
    value: 2.04e12
    unit: dyn/cm2
    scope: material
    conditions: {unit_in_source: "20.4 x 10^11 dyn cm-2"}
    method: Printed as 20.4 x 10^11 dyn cm-2 and converted to 2.04e12 for entry; the printed value is kept in conditions.unit_in_source
    status: ground
    source: ioffe-thermal
    where: "Basic parameters table, Bulk modulus row (attributed to Bougrov et al. 2001)"
  - benchmark: thermal_conductivity
    value: 1.3
    unit: W cm-1 degC-1
    scope: material
    conditions: {temperature: "not printed in the table row", structure: "table block covers zinc blende and wurtzite"}
    method: Tabulated value as printed; the remark cites Sichel and Pankove (1977) and Chow and Ghezzo (1996)
    status: ground
    source: ioffe-thermal
    where: "Basic parameters table, Thermal conductivity row (block headed Zinc Blende (cubic) and Wurtzite (hexagonal))"
  - benchmark: bandgap
    value: 3.39
    unit: eV
    scope: material
    conditions: {structure: wurtzite, temperature: "300 K"}
    method: Tabulated value cited to Chow and Ghezzo (1996)
    status: ground
    source: ioffe-bandstr
    where: "Basic Parameters for Wurtzite crystal structure, Energy gaps E g row, 300 K"
  - benchmark: bandgap
    value: 3.47
    unit: eV
    scope: material
    conditions: {structure: wurtzite, temperature: "0 K"}
    method: Tabulated value cited to Bougrov et al. (2001)
    status: ground
    source: ioffe-bandstr
    where: "Basic Parameters for Wurtzite crystal structure, Energy gaps E g row, 0 K"
  - benchmark: breakdown_field
    value: 5000000
    unit: V/cm
    scope: material
    conditions: {structure: wurtzite, temperature: "300 K", approximate: "printed as ~5 x 10^6 V cm-1"}
    method: Approximate value as printed in the Ioffe electrical properties table (no attribution printed for this row)
    status: ground
    source: ioffe-ebasic
    where: "Basic Parameters for Wurtzite crystal structure, Breakdown field row"
  - benchmark: breakdown_field
    value: 3300000
    unit: V/cm
    scope: material
    conditions: {structure: wurtzite, temperature: "300 K"}
    method: Value printed in the same table with the remark Chow and Ghezzo (1996); lower than the approximate value above
    status: ground
    source: ioffe-ebasic
    where: "Basic Parameters for Wurtzite crystal structure, Breakdown field row with remark Chow and Ghezzo (1996)"
  - benchmark: electron_mobility
    value: 440
    unit: cm2/(V s)
    scope: material
    conditions: {bound: "upper limit as printed (=<)", temperature: "300 K", material: "purest material, n about 10^17 cm-3"}
    method: Upper limit as printed on the Ioffe Hall effect page, cited to Ilegems (1972) and Ilegems and Dingle (1973)
    status: ground
    source: ioffe-hall
    where: "Mobility and Hall Effect page, Mobility electrons row"
  - benchmark: electron_mobility
    value: 1000
    unit: cm2/(V s)
    scope: material
    conditions: {bound: "upper limit as printed (=<)", temperature: "300 K", doping: "not stated"}
    method: Upper limit as printed in the Ioffe electrical table for wurtzite GaN; it conflicts with the 440 cm2/(V s) figure from the Hall page, and both are kept
    status: ground
    source: ioffe-ebasic
    where: "Basic Parameters for Wurtzite crystal structure, Mobility electrons row"
  - benchmark: hole_mobility
    value: 200
    unit: cm2/(V s)
    scope: material
    conditions: {bound: "upper limit as printed (=<)", temperature: "300 K"}
    method: Upper limit as printed in the Ioffe electrical table for wurtzite GaN
    status: ground
    source: ioffe-ebasic
    where: "Basic Parameters for Wurtzite crystal structure, Mobility holes row"
  - benchmark: electron_affinity
    value: 4.1
    unit: eV
    scope: material
    conditions: {structure: wurtzite, temperature: "300 K"}
    method: Tabulated value attributed to Bougrov et al. (2001)
    status: ground
    source: ioffe-basic
    where: "Basic Parameters for Wurtzite crystal structure, Electron affinity row"
  - benchmark: dielectric_constant
    value: 8.9
    unit: dimensionless
    scope: material
    conditions: {frequency: "static", structure: wurtzite, temperature: "300 K"}
    method: Tabulated value as printed
    status: ground
    source: ioffe-basic
    where: "Basic Parameters for Wurtzite crystal structure, Dielectric constant (static) row"
  - benchmark: dielectric_constant
    value: 5.35
    unit: dimensionless
    scope: material
    conditions: {frequency: "high frequency", structure: wurtzite, temperature: "300 K"}
    method: Tabulated value attributed to Bougrov et al. (2001)
    status: ground
    source: ioffe-basic
    where: "Basic Parameters for Wurtzite crystal structure, Dielectric constant (high frequency) row"
  - benchmark: lattice_constant
    value: 3.189
    unit: Å
    scope: material
    conditions: {axis: "a", structure: wurtzite, temperature: "300 K"}
    method: Value attributed to Qian et al. (1996) as printed
    status: ground
    source: ioffe-basic
    where: "Basic Parameters for Wurtzite crystal structure, Lattice constant a row, 300 K"
  - benchmark: lattice_constant
    value: 5.186
    unit: Å
    scope: material
    conditions: {axis: "c", structure: wurtzite, temperature: "300 K"}
    method: Value attributed to Bougrov et al. (2001) as printed
    status: ground
    source: ioffe-basic
    where: "Basic Parameters for Wurtzite crystal structure, Lattice constant c row, 300 K"
  - benchmark: cte
    value: 5.59e-6
    unit: K-1
    scope: material
    conditions: {axis: "a", structure: wurtzite}
    method: Thermal expansion coefficient along a as printed (attributed to Qian et al. 1996)
    status: ground
    source: ioffe-basic
    where: "Basic Parameters for Wurtzite crystal structure, Thermal expansion coefficient a row"
  - benchmark: electron_effective_mass
    value: 0.20
    unit: m0
    scope: material
    conditions: {structure: wurtzite, temperature: "300 K"}
    method: Value attributed to Bougrov et al. (2001); the same table lists 0.27 m0 from Rheinlander and Neumann (1974), which is not used here
    status: ground
    source: ioffe-basic
    where: "Basic Parameters for Wurtzite crystal structure, Effective electron mass m e row"
story:
  recipe:
    line: "GaN is a binary compound with one gallium atom for each nitrogen atom. The Ioffe archive gives the wurtzite structure,."
    parts:
      - name: Gallium
        symbol: Ga
        atoms: 1
        role: "Group III metal. Gallium and nitrogen form the covalent bonds of the crystal, and gallium is the element that supply is tight for (see supply)."
      - name: Nitrogen
        symbol: N
        atoms: 1
        role: "Group V element. Nitrogen forms the other half of the 1:1 lattice."
  risk_groups:
    - title: "For people"
      level: 1
      verdict: "Skin sensitizer in the PubChem GHS aggregate"
      lead: "PubChem's aggregated GHS data give a skin sensitization statement (H317) for most company reports. The sources read here give no exposure limit for GaN."
      points:
        - label: "The powder"
          line: "PubChem reports H317 (may cause an allergic skin reaction) in 97.8% of 45 company reports, with a Warning signal word. About 2.2% of reports say the chemical does not meet GHS hazard criteria."
        - label: "Dust and breathing"
          line: "The PubChem hazards summary cites RTECS for lung fibrosis in rats after intratracheal lethal-dose studies. These are summary entries, not a full toxicology study."
  why: "Gallium nitride (GaN) is a wide-bandgap semiconductor. It crystallizes in the wurtzite structure, with a band gap of 3.39 eV at 300 K in one table of the Ioffe archive. That band gap and a breakdown field of about 5 x 10^6 V/cm let GaN switch high voltages in small devices. The sources read here do not describe the manufacturing route."
  uses:
    - where: "Power electronics"
      line: "The EPC2045 datasheet describes a 100 V enhancement-mode GaN power transistor with RDS(on) of 7 mOhm and a continuous drain current of 16 A. It lists open-rack server power, lidar and pulsed power, and isolated power supplies as uses."
    - where: "Integrated circuits and optoelectronics"
      line: "The USGS reports that GaN is used to make integrated circuits and optoelectronic devices. ICs accounted for 73% of domestic gallium consumption and optoelectronic devices for 26%, and the USGS lists defense, high-performance computing and telecommunications among the IC uses."
    - where: "Defense and space electronics"
      line: "The USGS states that GaAs- and GaN-based ICs are used in many defense-related applications, where it says no effective substitutes exist. NASA tested EPC1001 GaN transistors for space-related use, though only on the ground and at the device level."
  can_do:
    - label: "Act as a wide-bandgap semiconductor"
      benchmark: bandgap
      value: "3.39 eV at 300 K"
      line: "Ioffe lists 3.39 eV at 300 K (Chow and Ghezzo 1996) and 3.47 eV at 0 K (Bougrov et al. 2001). A wide band gap is the property that the Ioffe archive lists as the reason for high-voltage use; the archive itself does not state the consequence."
    - label: "Hold a high electric field"
      benchmark: breakdown_field
      value: "about 5 x 10^6 V/cm"
      line: "The approximate breakdown field in the Ioffe table is about 5 x 10^6 V/cm, and another remark in the same table gives 3.3 x 10^6 V/cm. The two numbers differ, so use the one that matches the test condition."
    - label: "Carry heat"
      benchmark: thermal_conductivity
      value: "1.3 W cm-1 degC-1"
      line: "Ioffe gives a thermal conductivity of 1.3 W cm-1 degC-1 with no temperature printed in the row. Heat spreading in a device was not sourced here."
    - label: "Move electrons"
      benchmark: electron_mobility
      value: "at most 440 cm2/(V s)"
      line: "The Ioffe Hall page gives an electron mobility of at most 440 cm2/(V s) in the purest material at 300 K. The electrical table gives at most 1000 cm2/(V s) with no doping stated. The Ioffe archive also has a separate page for the two-dimensional electron gas at AlGaN/GaN interfaces, which was not read in this run."
  compare: "GaN sits at the wide-bandgap end of the semiconductor family. Its band gap of 3.39 eV at 300 K and its breakdown field of about 5 x 10^6 V/cm are the numbers that set it apart in the Ioffe tables. Its electron mobility is modest, at most 440 cm2/(V s) in the purest material, and that figure caps how fast it can switch. The sources read here give no like-for-like comparison with other materials, so no ranking is made in this profile."
  compare_rows:
    - label: "Band gap"
      benchmark: bandgap
    - label: "Breakdown field"
      benchmark: breakdown_field
    - label: "Thermal conductivity"
      benchmark: thermal_conductivity
  handling:
    - "PubChem lists precautionary statements for GaN, including avoiding breathing dust and wearing protective gloves. Follow them when handling powder."
    - "The GHS sensitization statement (97.8% of reports) means skin contact should be avoided. Wear gloves and wash after handling."
    - "No supplier safety data sheet for GaN powder was read in this run, so check the SDS for the product you handle."
  good_for:
    - "Wide band gap. The Ioffe table gives 3.39 eV at 300 K, which is what allows high-voltage switching in small devices."
    - "Breakdown field. The approximate value of 5 x 10^6 V/cm supports high-voltage devices with thin layers."
    - "Radiation tolerance at device level. In NASA ground tests, all eight EPC1001 transistors remained functional after heavy-ion irradiation and 1000 thermal cycles."
  watch_out:
    - "Electron mobility is limited. The sources give at most 440 cm2/(V s) in the purest material, and the electrical table gives up to 1000 cm2/(V s) with no doping stated."
    - "Gallium supply is concentrated. The USGS says China accounted for 99% of worldwide primary low-purity gallium production, and US imports supply all of its gallium."
    - "Radiation and cycling tests are device-level. They do not show that the GaN material itself is radiation-hard, and irradiated devices showed higher leakage current."
  verdict: "GaN is a well-documented wide-bandgap semiconductor. Its band gap, density, melting point and thermal conductivity are printed in the Ioffe archive. The space-related evidence is limited to ground tests of one transistor family, and the supply of gallium is concentrated in China."
risks:
  hazards:
    - text: "PubChem aggregates the GHS classifications for GaN and reports skin sensitization (H317, Skin Sens. 1) in 97.8% of 45 company reports, with a Warning signal word. About 2.2% of reports say the chemical does not meet GHS hazard criteria."
      ghs: ["H317"]
      source: pubchem-gan
      where: "Safety and Hazards, GHS Classification (CID 117559)"
    - text: "The PubChem hazards summary cites RTECS for lung fibrosis in rats after intratracheal lethal-dose studies, and for irritation and skin sensitization. These are summary entries, not a full toxicology study."
      ghs: []
      source: pubchem-gan
      where: "Safety and Hazards, Hazards Summary"
  failure_risks:
    - mode: "Heavy-ion irradiation of EPC1001 GaN transistors (device level)"
      trigger: "Au 2342 MeV and Xe 1569 MeV ions, doses 7886 to 22718 rad as printed"
      consequence: "The main impact was an increase in leakage current. All eight parts (four control, four irradiated) remained functional."
      source: nasa-epc1001-2012
      where: "Test matrix table and Observations slide"
    - mode: "Thermal cycling of EPC1001 transistors (device level)"
      trigger: "1000 cycles between -55 and +125 degC"
      consequence: "Transconductance varied inconsistently between devices, and RDS(on) at 1000 cycles fell into two clusters that differ at p below 0.005 (cause unknown)."
      source: nasa-epc1001-2012
      where: "Observations slide"
  side_effects: []
  handling:
    - text: "PubChem lists precautionary statements for GaN, including P261 (avoid breathing dust), P272, P280 (wear protective gloves), P302+P352 (if on skin, wash with plenty of water), P321, P333+P317, P362+P364 and P501."
      source: pubchem-gan
      where: "GHS Classification, Precautionary Statement Codes"
  mitigations: []
corrosion:
  - environment: "Thermal cycling between -55 and +125 degC, 1000 cycles (device level, EPC1001 transistors)"
    headline: "All eight tested transistors remained functional after 1000 cycles."
    effect: "Threshold voltage fell at first and levelled off after about 130 cycles. Output characteristics varied from cycle to cycle, and RDS(on) fell into two clusters at 1000 cycles, with the cause unknown."
    source: nasa-epc1001-2012
    where: "Observations slide and the thermal cycling figures"
  - environment: "Heavy-ion irradiation (Au 2342 MeV; Xe 1569 MeV), doses 7886 to 22718 rad as printed"
    headline: "Irradiated devices stayed functional, with higher leakage current as the main change."
    effect: "The main impact of radiation was an increase in leakage current. Irradiated parts were more stable in RDS(on) than expected during cycling."
    source: nasa-epc1001-2012
    where: "Test matrix table and Observations slide"
uses:
  - application: electronics-and-chips
    device: "GaN power transistor (EPC2045, 100 V)"
    example: "The datasheet lists open-rack server architectures, lidar and pulsed power, and isolated power supplies as applications."
    source: epc2045-ds
    where: "Front page, application list"
  - application: electronics-and-chips
    device: "GaN integrated circuits and optoelectronic devices"
    example: "The USGS lists defense, high-performance computers and telecommunications for ICs, and aerospace, consumer goods, industrial and medical equipment for optoelectronic devices."
    source: usgs-mcs2026-gallium
    where: "Domestic Production and Use paragraph"
  - application: electronics-and-chips
    device: "EPC1001 enhancement-mode GaN transistor (ground test)"
    example: "Eight parts survived heavy-ion irradiation with doses up to 22718 rad and 1000 thermal cycles, all still functional."
    source: nasa-epc1001-2012
    where: "Observations slide"
supply:
  - subject: Gallium
    abundance: "Not read in a source for this profile (the USGS gallium chapter does not give crustal abundance)"
    producers:
      - country: China
        share_percent: 99
        year: 2025
    critical_lists: []
    recycling: "USGS: old scrap is not recovered. New scrap from GaAs device manufacture is reprocessed to recover high-purity gallium at one facility in New York."
    substitutes:
      - "USGS: silicon is the principal competitor with GaAs in solar cells. No effective substitute is listed for GaAs or GaN in many defense-related applications."
    source: usgs-mcs2026-gallium
    where: "World Low-Purity Production table, Events, Trends and Issues, Recycling and Substitutes sections. Chinese share is the text statement that China accounted for 99% of primary low-purity production."
gaps:
  - "No flight, vacuum or space-environment result for GaN material was found. The only space-related tests read are ground heavy-ion and thermal-cycling tests of EPC1001 transistors, which are device-level results."
  - "Phone-charger, satellite and 5G RF uses are not in any source read in this run, so they are not written."
  - "Crustal abundance of gallium was not found in a fetched source."
  - "Critical-mineral list status for gallium was not found in the USGS text read (USGS 2025 list and EU CRM list not opened)."
  - "Atomic weights of Ga and N were not read (the NIST page did not return single-element data in this run), so the recipe parts carry no atomic_weight."
  - "The manufacturing route (MOCVD, HVPE or other) is not sourced."
  - "No supplier safety data sheet for GaN powder was read; hazard data rest on the PubChem GHS aggregate and the RTECS summary."
  - "Corrosion or chemical resistance of GaN in humid or acidic environments was not found."
  - "The Ioffe thermal conductivity row is shared by zinc blende and wurtzite, so the 1.3 W cm-1 degC-1 value is not split by structure."
  - "Two electron mobility limits (440 and 1000 cm2/(V s)) conflict; both are kept with their conditions."
  - "A GaN review on arXiv was not retrieved in this run (the arXiv query returned no entries)."
  - "Navitas GaN datasheet URL did not return a PDF in this run."
sources:
  ioffe-basic:
    title: "NSM Archive: Gallium Nitride (GaN), Basic Parameters"
    id: "Ioffe Institute NSM Archive, GaN basic parameters"
    url: "http://www.ioffe.ru/SVA/NSM/Semicond/GaN/basic.html"
    kind: database
    license: "Cited, not reproduced (Ioffe NSM Archive)"
  ioffe-thermal:
    title: "NSM Archive: Gallium Nitride (GaN), Thermal Properties"
    id: "Ioffe Institute NSM Archive, GaN thermal properties"
    url: "http://www.ioffe.ru/SVA/NSM/Semicond/GaN/thermal.html"
    kind: database
    license: "Cited, not reproduced (Ioffe NSM Archive)"
  ioffe-bandstr:
    title: "NSM Archive: Gallium Nitride (GaN), Band Structure and Carrier Concentration"
    id: "Ioffe Institute NSM Archive, GaN band structure"
    url: "http://www.ioffe.ru/SVA/NSM/Semicond/GaN/bandstr.html"
    kind: database
    license: "Cited, not reproduced (Ioffe NSM Archive)"
  ioffe-ebasic:
    title: "NSM Archive: Gallium Nitride (GaN), Basic Electrical Parameters"
    id: "Ioffe Institute NSM Archive, GaN electrical parameters"
    url: "http://www.ioffe.ru/SVA/NSM/Semicond/GaN/ebasic.html"
    kind: database
    license: "Cited, not reproduced (Ioffe NSM Archive)"
  ioffe-hall:
    title: "NSM Archive: Gallium Nitride (GaN), Mobility and Hall Effect"
    id: "Ioffe Institute NSM Archive, GaN mobility and Hall effect"
    url: "http://www.ioffe.ru/SVA/NSM/Semicond/GaN/hall.html"
    kind: database
    license: "Cited, not reproduced (Ioffe NSM Archive)"
  pubchem-gan:
    title: "PubChem compound summary: Gallium nitride (CID 117559)"
    id: "PubChem CID 117559"
    url: "https://pubchem.ncbi.nlm.nih.gov/compound/117559"
    kind: database
    license: "Public domain (PubChem)"
  usgs-mcs2026-gallium:
    title: "Mineral Commodity Summaries 2026: Gallium"
    id: "USGS MCS 2026, gallium"
    url: "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-gallium.pdf"
    year: 2026
    kind: report
    license: "Public domain (USGS)"
  nasa-epc1001-2012:
    title: "Effects of Radiation and Long-Term Thermal Cycling on EPC 1001 Gallium Nitride Transistors"
    id: "NASA NTRS 20120016796"
    url: "https://ntrs.nasa.gov/citations/20120016796"
    year: 2012
    kind: report
    license: "Public domain (NASA)"
  nasa-epc1001-2013:
    title: "Radiation and Thermal Cycling Effects on EPC1001 Gallium Nitride Power Transistors"
    id: "NASA NTRS 20130001606"
    url: "https://ntrs.nasa.gov/citations/20130001606"
    year: 2013
    kind: report
    license: "Public domain (NASA)"
  epc2045-ds:
    title: "EPC2045 enhancement-mode GaN power transistor datasheet"
    id: "EPC EPC2045 datasheet"
    url: "https://www.epc-co.com/epc/Portals/0/epc/documents/datasheets/EPC2045_datasheet.pdf"
    kind: datasheet
    license: "Cited, not reproduced (EPC)"
documents:
  - title: "NSM Archive: Gallium Nitride (GaN), Basic Parameters"
    type: database
    url: "http://www.ioffe.ru/SVA/NSM/Semicond/GaN/basic.html"
  - title: "PubChem compound summary: Gallium nitride (CID 117559)"
    type: database
    url: "https://pubchem.ncbi.nlm.nih.gov/compound/117559"
  - title: "Mineral Commodity Summaries 2026: Gallium"
    type: report
    url: "https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-gallium.pdf"
    year: 2026
  - title: "Effects of Radiation and Long-Term Thermal Cycling on EPC 1001 Gallium Nitride Transistors"
    type: report
    url: "https://ntrs.nasa.gov/citations/20120016796"
    year: 2012
  - title: "Radiation and Thermal Cycling Effects on EPC1001 Gallium Nitride Power Transistors"
    type: report
    url: "https://ntrs.nasa.gov/citations/20130001606"
    year: 2013
  - title: "EPC2045 enhancement-mode GaN power transistor datasheet"
    type: datasheet
    url: "https://www.epc-co.com/epc/Portals/0/epc/documents/datasheets/EPC2045_datasheet.pdf"
license: CC-BY-4.0
updated: "2026-10-19"
review:
  status: draft
  method: assistant
  checked_values: 19
  unreachable: 1
  caveats: 1
  note: "Written by an AI assistant on 2026-10-19 from pages read in this run. Values were copied from the fetched pages and have not been re-checked by a second reader."