Calcium titanate CaTiO3

spore: profile
id: calcium-titanate
spore_version: 0.2
family: oxide-ceramics
name: Calcium titanate
abbreviation: CaTiO3
role: perovskite oxide ceramic for microwave dielectrics and nuclear wasteforms
category: ceramics
type: oxides
summary: |
  Calcium titanate (CaTiO3) is a perovskite oxide that also occurs as the mineral perovskite. A supplier safety data sheet describes a beige, insoluble powder with a melting point of 1975 °C and a density of 4.1 g/cc. A 2022 study of a sintered ceramic measured a relative permittivity of 145.97 and a Q times f of 4020 GHz, and a 2021 study of zirconolite wasteforms found that its perovskite phase was preferentially leached by strong acid.
best_for: Microwave dielectric resonator ceramics, usually in composites with a material that offsets its large temperature coefficient
weakest_at: Large positive temperature coefficient of resonant frequency (796.69 ppm/°C in the 2022 sintered ceramic), and preferential leaching of the perovskite phase in strong acid
identity:
  formula: CaTiO3
  cas: 12049-50-2
  crystal_system: orthorhombic
  space_group: Pnma
  source: angstrom-sds
  where: Angstrom Sciences SDS, Section 1 (CAS Number 12049-50-2, EC Number 234-988-1) and Section 9 (molecular weight 135.94 g/mol); space group Pnma from the high-pressure study arXiv 1006.4423; PubChem CID 162251 gives molecular formula CaO3Ti and molecular weight 135.94
tags:
  environments: []
  stresses: []
  applications:
    - electronics-and-chips
properties:
  - benchmark: density
    label: Density, powder (Angstrom Sciences SDS)
    value: 4.1
    unit: g/cc
    scope: material
    conditions:
      form: powder, product as supplied (CAS 12049-50-2)
      temperature: not stated on the sheet
    method: Value printed in a supplier safety data sheet, Section 9
    status: ground
    source: angstrom-sds
    where: Section 9, Density row
  - benchmark: density
    label: Theoretical density, sintered ceramic (Rietveld)
    value: 4.026
    unit: g/cm3
    scope: material
    conditions:
      form: ceramic sintered at 1250 °C from CaCO3 and TiO2
      basis: calculated from X-ray diffraction data by Rietveld refinement
    method: Theoretical density printed in Table 2 (as g cm-3) for the CT row; not a measured density
    status: calculated
    source: jmmm-cto2022
    where: Table 2, rho theory column, CT row
  - benchmark: density
    label: Apparent density, sintered ceramic (Archimedes)
    value: 3.859
    unit: g/cm3
    scope: material
    conditions:
      form: ceramic sintered at 1250 °C from CaCO3 and TiO2
      basis: Archimedes immersion of the pellet
    method: Apparent density printed in Table 2 (as g cm-3) for the CT row, measured by the Archimedes method
    status: ground
    source: jmmm-cto2022
    where: Table 2, rho apparent column, CT row
  - benchmark: relative_density
    label: Relative density, sintered ceramic
    value: 95.852
    unit: '%'
    scope: material
    conditions:
      form: ceramic sintered at 1250 °C from CaCO3 and TiO2
    method: Ratio of apparent to theoretical density, printed in Table 2
    status: ground
    note: The abstract of the same study says the relative density is below 90 percent. That conflicts with Table 2, so the table value is kept and the conflict is noted in gaps.
    source: jmmm-cto2022
    where: Table 2, rho relative column, CT row
  - benchmark: melting_point
    label: Melting point, powder (Angstrom Sciences SDS)
    value: 1975
    unit: °C
    scope: material
    conditions:
      form: powder, product as supplied
    method: Value printed in a supplier safety data sheet, Section 9
    status: ground
    source: angstrom-sds
    where: Section 9, Melting Point row
  - benchmark: dielectric_constant
    label: Relative permittivity, sintered ceramic (this work)
    value: 145.97
    unit: '-'
    scope: material
    conditions:
      form: ceramic sintered at 1250 °C from CaCO3 and TiO2, solid-state route
      test: Hakki-Coleman dielectric resonator method
      frequency: not stated in the text
      processing: precursors calcined at 1100 °C for 4 h, sintered at 1250 °C
    method: Value printed in Table 3 under 'This work' for the CT row, measured with the Hakki-Coleman dielectric resonator method
    status: ground
    source: jmmm-cto2022
    where: Table 3, epsilon r column, CT row, This work
  - benchmark: q_times_f
    label: Quality factor times frequency, sintered ceramic (this work)
    value: 4020
    unit: GHz
    scope: material
    conditions:
      form: ceramic sintered at 1250 °C from CaCO3 and TiO2
      test: Hakki-Coleman dielectric resonator method
      frequency: not stated in the text
    method: Q times f value printed in Table 3 under 'This work' for the CT row
    status: ground
    note: q_times_f is not yet in spores/property-canon.yaml. It is a short snake_case name, as the brief allows.
    source: jmmm-cto2022
    where: Table 3, Q times f column, CT row, This work
  - benchmark: tau_f
    label: Temperature coefficient of resonant frequency, sintered ceramic (this work)
    value: 796.69
    unit: ppm/°C
    scope: material
    conditions:
      form: ceramic sintered at 1250 °C from CaCO3 and TiO2
      test: Hakki-Coleman dielectric resonator method
    method: Value printed as ppm/℃ in Table 3 under 'This work' for the CT row; calculated from resonant frequencies at two temperatures
    status: ground
    note: tau_f is not yet in spores/property-canon.yaml. It is a short snake_case name, as the brief allows.
    source: jmmm-cto2022
    where: Table 3, tau f column, CT row, This work
  - benchmark: bulk_modulus
    label: Bulk modulus K0, single crystal (equation-of-state fit)
    value: 181
    unit: GPa
    scope: material
    conditions:
      form: single crystal, room temperature starting point
      pressure_range: 0 to 40 GPa
      k0_prime: constrained to 4 in the fit
    method: Equation-of-state fit to X-ray pressure data (K0 printed as 181.0(6) GPa); the uncertainty in parentheses is in the last digit
    status: ground
    uncertainty: (6) in the last digit of 181.0
    source: guennou2010
    where: Section 3 (equation of state), Table II, K0 row, this work
  - benchmark: dielectric_constant
    label: Relative permittivity, CaTiO3 from earlier work (ref 16, for comparison)
    value: 170
    unit: '-'
    scope: material
    conditions:
      form: CaTiO3 ceramic from the earlier work cited as reference 16
      basis: literature value listed in Table 3, not measured in the 2022 study
    method: Value printed in Table 3 on the second line of the CT row, under the reference column
    status: ground
    source: jmmm-cto2022
    where: Table 3, epsilon r column, CT row, reference [16]
  - benchmark: q_times_f
    label: Quality factor times frequency, CaTiO3 from earlier work (ref 16, for comparison)
    value: 3600
    unit: GHz
    scope: material
    conditions:
      form: CaTiO3 ceramic from the earlier work cited as reference 16
      basis: literature value listed in Table 3, not measured in the 2022 study
    method: Q times f value printed in Table 3 on the second line of the CT row
    status: ground
    note: The introduction of the same study quotes Q times f of about 3,600 GHz for this reference, so the table and text agree here.
    source: jmmm-cto2022
    where: Table 3, Q times f column, CT row, reference [16]
  - benchmark: tau_f
    label: Temperature coefficient of resonant frequency, CaTiO3 from earlier work (ref 16, for comparison)
    value: 800.12
    unit: ppm/°C
    scope: material
    conditions:
      form: CaTiO3 ceramic from the earlier work cited as reference 16
      basis: literature value listed in Table 3, not measured in the 2022 study
    method: Value printed as ppm/℃ in Table 3 on the second line of the CT row
    status: ground
    note: The introduction of the same study quotes about 1800 ppm/°C for this reference. Table 3 prints 800.12, which is used here, and the conflict is noted in gaps.
    source: jmmm-cto2022
    where: Table 3, tau f column, CT row, reference [16]
corrosion:
  - environment: Strong acids at 90 °C, as a perovskite accessory phase in a zirconolite wasteform (1 M H2SO4 and 8 M HNO3)
    headline: Acid leaching preferentially dissolves the calcium titanate perovskite phase; 2.6 wt.% remained after 1 M H2SO4 and 3.8 wt.% after 8 M HNO3.
    effect: In a study of zirconolite nuclear wasteforms with an accessory perovskite phase (nominally Ce-bearing CaTiO3), the perovskite diffraction peak fell in every leaching medium, so the phase was preferentially leached. Sulfuric acid was the most effective, and after 8 M HNO3 about one-third of the original perovskite remained. The paper gives the dissolution reaction CaTiO3 + (6-x)H+ gives Ca2+ + Ti(OH)x(4-x)+ + (3-x)H2O, and it reports TiO2 precipitates on the surface.
    rating: moderate
    conditions:
      basis: accelerated static leaching of powders, 7 d per medium with 14 d cumulative, measured by X-ray diffraction after leaching
      temperature: 90 °C
      form: zirconolite ceramic with accessory perovskite
    source: blackburn2021
    where: Results (Table 1 phase fractions; perovskite peak after leaching); Discussion (reaction equation 1)
  - environment: Strong oxidizing agents
    headline: The supplier sheet lists oxidizing agents as incompatible. No test or corrosion rate was found.
    effect: The Angstrom Sciences sheet lists oxidizing agents as the reactivity hazard and asks for storage apart from listed incompatible conditions. The sheet gives no test or rate for calcium titanate with an oxidizer.
    rating: unknown
    conditions:
      basis: incompatibility statement in a supplier SDS; no test
      form: powder
    source: angstrom-sds
    where: Section 10 (Reactivity; Incompatible Conditions)
  - environment: Water and humidity
    headline: The powder is insoluble in water according to the supplier. No humidity-ageing test was found.
    effect: The Angstrom Sciences sheet gives water solubility as insoluble. No study of dielectric or mechanical change after humid storage was found in a source read in this run.
    rating: unknown
    conditions:
      basis: solubility statement only
      form: powder
    source: angstrom-sds
    where: Section 9 (Water Solubility)
risks:
  hazards:
    - text: 'PubChem records the substance as not classified: 18 of 19 company reports say it does not meet GHS hazard criteria, and only 5.3 percent of companies gave GHS information.'
      ghs: []
      source: pubchem-cto
      where: GHS Classification section (CID 162251)
    - text: The Angstrom Sciences sheet (revised 2015) gives no signal word and no hazard statements, and an HMIS health rating of 1. It says the powder may cause irritation to the eyes, skin, and on inhalation or ingestion, with no numeric toxicity value.
      ghs: []
      source: angstrom-sds
      where: Sections 2 and 11
  failure_risks:
    - mode: Preferential dissolution of the perovskite phase in strong acid
      trigger: Acid leaching at 90 °C (1 M H2SO4 or 8 M HNO3) of a zirconolite wasteform that holds CaTiO3 as an accessory phase
      consequence: Residual perovskite fell to 2.6 wt.% after 1 M H2SO4 and 3.8 wt.% after 8 M HNO3. The study says the perovskite phase is postulated to increase the release of plutonium to leachants, and that cerium release tracked the amount of perovskite present.
      severity: high
      source: blackburn2021
      where: Introduction; Results (Table 1 and the perovskite peak after leaching); Discussion
    - mode: Large drift of the resonant frequency with temperature
      trigger: Pure CaTiO3 used as a microwave resonator without a compensating partner phase
      consequence: The sintered pure ceramic has a temperature coefficient of resonant frequency of 796.69 ppm/°C, so its resonant frequency moves strongly with temperature. The authors note that CaTiO3-based ceramics have mostly been used as one component of composites.
      severity: moderate
      source: jmmm-cto2022
      where: Table 3 (CT row); Introduction
    - mode: Residual porosity in a sintered ceramic
      trigger: Sintering at 1250 °C, the schedule used for the pure ceramic in the 2022 study
      consequence: Table 2 gives a relative density of 95.852 percent, but the abstract says the relative density is below 90 percent. Porosity therefore needs to be measured for each batch before a dielectric value is relied on.
      severity: low
      source: jmmm-cto2022
      where: Table 2; abstract
  side_effects: []
  handling:
    - text: Store in a cool, dry place in a tightly sealed container, apart from oxidizing agents and the other materials listed as incompatible.
      source: angstrom-sds
      where: Section 7 (Conditions for safe storage) and Section 10
    - text: Take care not to raise dust. Clean up spills with a HEPA filter vacuum into a closed container, and do not blow dust off clothing or skin with compressed air.
      source: angstrom-sds
      where: Section 6 (Accidental release measures) and Section 7 (Work/Hygienic Maintenance)
    - text: Wear safety glasses or goggles, rubber gloves and protective work clothing, as the sheet specifies.
      source: angstrom-sds
      where: Section 8 (Protective Gloves, Eye Protection, Body Protection)
  mitigations:
    - text: Provide sufficient ventilation to keep airborne concentrations at or below the threshold limit value. The sheet prints no numeric limit (N/A).
      source: angstrom-sds
      where: Section 7 (Ventilation) and Section 8 (Threshold Limit Value)
uses:
  - application: electronics-and-chips
    device: Microwave dielectric resonator ceramic
    example: A 2022 study measured a relative permittivity of 145.97 and a Q times f of 4020 GHz for a pure CaTiO3 sintered ceramic. Its introduction says CaTiO3-based ceramics have mostly been used as one component of composites, because of their moderate permittivity and positive temperature coefficient.
    source: jmmm-cto2022
    where: Introduction; Table 3, CT row
  - application: electronics-and-chips
    device: Microwave absorber (reported application)
    example: The 2022 study's introduction notes earlier work that showed CaTiO3 can be applied to microwave absorption in the X and Ku bands. Only the introduction states this, so it is a reported application, not a result of the study.
    source: jmmm-cto2022
    where: Introduction
supply:
  - subject: Titanium (titanium sponge metal, 2025; the oxide feedstock of CaTiO3 is not covered by this source)
    producers:
      - country: China
        share_percent: 70.3
        year: 2025
      - country: Japan
        share_percent: 14.3
        year: 2025
      - country: Russia
        share_percent: 6.8
        year: 2025
      - country: Kazakhstan
        share_percent: 4.3
        year: 2025
    critical_lists: []
    recycling: 'USGS: consumption data for titanium scrap for the titanium metal industry were withheld in 2025, and scrap consumption data for the steel, superalloy and other industries were not available.'
    substitutes:
      - 'USGS: aluminum, nickel, specialty steels and zirconium alloys may be substituted for titanium where corrosion resistance is needed. This is a statement about metal uses, not oxide ceramics.'
    source: usgs-mcs2026-titanium
    where: World Sponge Metal Production table, 2025 column (world total 370,000 t; shares calculated by Space Mushroom against that total); Recycling; Substitutes
documents:
  - title: 'Angstrom Sciences safety data sheet: Calcium Titanium Oxide, CAS 12049-50-2 (revised 07/08/15)'
    type: sds
    url: https://angstromsciences.com/wp-content/uploads/files/SDS/Calcium%20Titanium%20Oxide.pdf
    year: 2015
  - title: 'PubChem: Calcium titanate (CID 162251), GHS classification summary'
    type: database
    url: https://pubchem.ncbi.nlm.nih.gov/compound/162251
    year: 2026
  - title: 'NIST: Atomic Weights and Isotopic Compositions for All Elements'
    type: database
    url: https://physics.nist.gov/cgi-bin/Compositions/stand_alone.pl
  - title: Effect of A-site modification on structural and microwave dielectric properties of calcium titanate (J. Met. Mater. Miner. 32(3), 2022)
    type: paper
    url: https://jmmm.material.chula.ac.th/index.php/jmmm/article/download/1525/1165
    year: 2022
  - title: Influence of accessory phases and surrogate type on accelerated leaching of zirconolite wasteforms (npj Materials Degradation 5, 24)
    type: paper
    url: https://eprints.whiterose.ac.uk/173147/9/s41529-021-00171-8.pdf
    year: 2021
  - title: High-pressure investigations of CaTiO3 up to 60 GPa using X-ray diffraction and Raman spectroscopy (arXiv:1006.4423)
    type: paper
    url: https://arxiv.org/pdf/1006.4423
    year: 2010
  - title: 'USGS Mineral Commodity Summaries 2026: Titanium and Titanium Dioxide'
    type: report
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-titanium.pdf
    year: 2026
  - title: 'SurfaceNet: Strontium titanate (SrTiO3) datasheet'
    type: datasheet
    url: https://surfacenet.de/files/kr_Strontium_Titanate.php
  - title: 'Stanford Advanced Materials: Material Safety Data Sheet, Strontium titanate (SrTiO3), version 2.0 (5 September 2012)'
    type: sds
    url: https://www.sputtertargets.net/Public/pdf/strontium-titanate-msds.pdf
    year: 2012
  - title: 'PubChem: Strontium titanium oxide (SrTiO3, CID 82899)'
    type: database
    url: https://pubchem.ncbi.nlm.nih.gov/compound/82899
    year: 2026
gaps:
  - No thermal conductivity, thermal expansion, hardness or refractive index for calcium titanate was found in a source read in this run. No band gap was read either.
  - The text does not state the measurement frequency for the pure CaTiO3 permittivity and Q times f values (Hakki-Coleman method, Table 3), so frequency is left out of the conditions.
  - q_times_f and tau_f are not in spores/property-canon.yaml. They are short snake_case names, as the brief allows, and need adding to the canon.
  - The 2022 study's introduction quotes about 1800 ppm/°C for reference 16, but Table 3 prints 800.12. The table value is kept.
  - The 2022 study's abstract gives relative density below 90 percent, but Table 2 gives 95.852 percent. The table value is kept.
  - No space, vacuum, outgassing, radiation or flight result for calcium titanate was found. Radiation tolerance of the Nd-doped ceramic was not read in a fetched source.
  - No humidity-ageing or long-term water study for calcium titanate was found. The corrosion entries rest on the SDS reactivity statement and on the zirconolite leaching study, which tested the perovskite as an accessory phase rather than the pure compound.
  - 'Calcium supply: no USGS chapter or other production source for calcium was read. The supply entry covers titanium as sponge metal, which is not the oxide feedstock of CaTiO3.'
  - Oxygen has no atomic weight here, because NIST prints an interval (15.99903 to 15.99977) rather than a single value. Atoms and atomic weight are given for calcium and titanium only.
  - 'Critical-mineral status for titanium was not read: the USGS critical-minerals list was not opened in this run, so critical_lists is empty.'
  - The American Elements calcium titanate SDS page returned a bot challenge. A second supplier SDS that a search result described as classifying the material as hazardous under OSHA could not be opened, so the hazard entries rest on the Angstrom sheet and PubChem.
  - Hazard data for the nanopowder form were not found. The classification refers to the bulk powder sheets read here.
  - 'Strontium titanate (related section): the SurfaceNet page prints the loss tangent and thermal conductivity with garbled units, and its thermal expansion coefficient has no unit printed, so none of these are given. Band gap and refractive index were not read in a primary source. No electronic-device or space data were read for strontium titanate.'
related:
  name: Strontium titanate
  abbreviation: SrTiO3
  formula: SrTiO3
  cas: 12060-59-2
  category: ceramics
  type: oxides
  summary: Strontium titanate (SrTiO3) is the related perovskite. Its supplier datasheet gives a density of 5.12 g/cm3, a melting point of 2080 °C and a Mohs hardness of 6 to 6.5. A 2012 supplier safety sheet gives a melting point of 2060.0 °C and prints no GHS codes.
  identity_note: Molecular weight is 183.52 in the 2012 safety sheet and 183.49 in PubChem (CID 82899). Both sources are for the same formula, SrTiO3.
  properties:
    - benchmark: density
      label: Density, strontium titanate (SurfaceNet datasheet)
      value: 5.12
      unit: g/cm3
      scope: material
      conditions:
        form: not stated on the page
      method: Value printed on a supplier datasheet, Density row
      status: ground
      source: sto-surfacenet
      where: Density row
    - benchmark: melting_point
      label: Melting point, strontium titanate (SurfaceNet datasheet)
      value: 2080
      unit: °C
      scope: material
      conditions:
        form: not stated on the page
      method: Value printed on a supplier datasheet, Melting point row
      status: ground
      source: sto-surfacenet
      where: Melting point row
    - benchmark: melting_point
      label: Melting point, powder (Stanford Advanced Materials sheet, 2012)
      value: 2060
      unit: °C
      scope: material
      conditions:
        form: powder
      method: Value printed in a 2012 supplier safety data sheet, Section III
      status: ground
      note: The two melting points differ by 20 °C, so the source of each is kept.
      source: sam-sto-msds
      where: Section III, Melting Point row
    - benchmark: hardness_mohs
      label: Mohs hardness, strontium titanate
      value: 6
      value_high: 6.5
      bound: range
      unit: '-'
      scope: material
      conditions:
        form: not stated on the page
      method: Printed as a Mohs range on a supplier datasheet
      status: ground
      source: sto-surfacenet
      where: Hardness row
    - benchmark: dielectric_constant
      label: Dielectric constant, strontium titanate (SurfaceNet datasheet)
      value: 300
      unit: '-'
      scope: material
      conditions:
        temperature: not stated on the page
        frequency: not stated on the page
      method: Value printed on a supplier datasheet with no test conditions
      status: ground
      source: sto-surfacenet
      where: Dielectric constant row
  hazards:
    - text: The 2012 Stanford Advanced Materials sheet prints no GHS codes. It calls strontium compounds of low toxicity and says their oxides and hydroxides are moderately caustic, and it places titanium oxide dust in the nuisance category.
      source: sam-sto-msds
      where: Section VI (Health Hazard Data)
    - text: The same sheet lists strong acids and strong bases as incompatible. In a fire it may emit toxic fumes, and the decomposition products are strontium oxide and titanium oxide.
      source: sam-sto-msds
      where: Section IV (Fire and Explosion Hazard Data); Section V (Reactivity Data)
story:
  recipe:
    line: CaTiO3 is a calcium titanium oxide with the perovskite structure, with one calcium ion, one titanium ion and three oxygen per formula unit. In the 2022 study, the ceramic was made by solid-state reaction of CaCO3 with TiO2. The precursors were calcined at 1100 °C for 4 h, then pressed and sintered at 1250 °C.
    parts:
      - name: Calcium
        symbol: Ca
        atoms: 1
        atomic_weight: 40.078
        role: The large cation in the perovskite framework. In the 2022 study it came from calcium carbonate (CaCO3).
        source: nist-atomic-weights
        where: Standard atomic weight column, Ca row (40.078(4))
      - name: Titanium
        symbol: Ti
        atoms: 1
        atomic_weight: 47.867
        role: The small cation at the centre of each oxygen octahedron. In the 2022 study it came from TiO2.
        source: nist-atomic-weights
        where: Standard atomic weight column, Ti row (47.867(1))
      - name: Oxygen
        symbol: O
        role: Three oxygen per formula unit, forming the tilted octahedral framework. NIST prints an interval for oxygen rather than one value, so no weight is given here.
        source: jmmm-cto2022
        where: Materials and methods (precursors); formula CaO3Ti from PubChem CID 162251
  risk_groups:
    - title: For people
      level: 0
      verdict: No hazard classification found
      lead: The supplier sheet and PubChem give no hazard classification for calcium titanate. The sheet lists only possible irritation.
      points:
        - label: The powder
          line: The Angstrom Sciences sheet gives no signal word and no hazard statements. PubChem reports that 18 of 19 company reports do not meet GHS criteria.
        - label: Irritation
          line: The sheet says the powder may irritate the eyes and skin, and may irritate if inhaled or swallowed. It gives no numeric toxicity value.
        - label: Dust
          line: Avoid raising dust. The sheet advises a HEPA filter vacuum for spills.
    - title: If it fails
      lead: These results come from leaching tests and resonator measurements, not from service incidents.
      points:
        - label: Acid
          line: In strong acid at 90 °C the perovskite phase of a zirconolite wasteform was preferentially dissolved. After 1 M H2SO4 it kept 2.6 wt.% and after 8 M HNO3 it kept 3.8 wt.%.
        - label: Temperature
          line: The pure sintered ceramic has a temperature coefficient of resonant frequency of 796.69 ppm/°C, so resonant frequency moves strongly with temperature.
        - label: Porosity
          line: Table 2 gives a relative density of 95.852 percent, but the abstract says below 90 percent. Measure porosity for each batch.
    - title: Handling and storage
      points:
        - label: Keep it dry and closed
          line: Store in a cool, dry place in a tightly sealed container, away from oxidizing agents.
        - label: Avoid dust
          line: Do not raise dust. Clean spills with a HEPA filter vacuum into a closed container, and do not blow dust off clothing with compressed air.
        - label: Ventilation
          line: Provide enough ventilation to keep the air at or below the threshold limit value. The sheet prints no numeric limit.
  why: Calcium titanate (CaTiO3) is a perovskite oxide, named after the mineral perovskite (Wikipedia credits the name to the Russian mineralogist Lev Perovski). Its structure is orthorhombic (space group Pnma), with tilted oxygen octahedra that lower the symmetry from the ideal cubic perovskite. The 2022 study measured a relative permittivity of 145.97 for a pure sintered ceramic. The 2021 nuclear study placed the same phase in SYNROC-type wasteforms, where it is a host for actinides but also the phase that is preferentially leached by strong acid. Its main limits are the large temperature coefficient of resonant frequency and that acid leaching.
  uses:
    - where: Microwave dielectric resonators
      line: The 2022 study measured a pure sintered CaTiO3 ceramic at a relative permittivity of 145.97 and a Q times f of 4020 GHz. Its introduction says CaTiO3 is mostly used as one component of microwave composites.
    - where: Nuclear wasteforms (SYNROC-type ceramic)
      line: The 2021 study notes that SYNROC-C, a wasteform for plutonium and other actinides, used zirconolite and perovskite as hosts. In its acid leach tests the perovskite phase was the one preferentially dissolved.
  can_do:
    - label: Permittivity
      value: '145.97'
      benchmark: dielectric_constant
      line: A pure sintered ceramic measured 145.97 in the 2022 study. The same table lists 170 for CaTiO3 from earlier work.
    - label: Quality factor
      value: 4020 GHz
      benchmark: q_times_f
      line: The Q times f of the pure sintered ceramic is 4020 GHz at a frequency that the text does not state.
    - label: Density
      value: 4.1 g/cc
      benchmark: density
      line: The Angstrom Sciences sheet gives a density of 4.1 g/cc for the powder. The sintered ceramic in the 2022 study had a theoretical density of 4.026 g/cm3.
    - label: Melting point
      value: 1975 °C
      benchmark: melting_point
      line: The supplier sheet gives a melting point of 1975 °C for the powder.
  compare: Calcium titanate is the lighter and lower-melting member of the perovskite family in this record. Its density is 4.1 g/cc and its melting point 1975 °C, against 5.12 g/cm3 and 2080 °C for strontium titanate in the related section. Its sintered permittivity of 145.97 is lower than the 300 that the strontium titanate datasheet quotes, although that datasheet prints no test conditions. Its large temperature coefficient of resonant frequency (796.69 ppm/°C) is the figure to check first when it is used in a resonator.
  compare_rows:
    - label: Density
      benchmark: density
    - label: Melting point
      benchmark: melting_point
    - label: Permittivity
      benchmark: dielectric_constant
  handling:
    - Store dry and sealed, away from oxidizing agents.
    - Avoid dust. Clean spills with a HEPA filter vacuum, and provide ventilation for dust-forming work.
    - The sheet prints no numeric exposure limit (TLV N/A).
  good_for:
    - Microwave resonators. The pure sintered ceramic has a relative permittivity of 145.97 and a Q times f of 4020 GHz.
    - Nuclear wasteform research. CaTiO3 is one host phase in SYNROC-type ceramics that hold plutonium and other actinides.
  watch_out:
    - Temperature drift. The pure sintered ceramic has a temperature coefficient of resonant frequency of 796.69 ppm/°C, so it needs a compensating partner material.
    - Acid durability. The perovskite phase was preferentially leached in 1 M H2SO4 and 8 M HNO3 at 90 °C.
    - Patchy data. No thermal expansion, hardness or thermal conductivity value for calcium titanate was found in a source read in this run.
  verdict: Calcium titanate is a stable, high-melting perovskite with a useful microwave permittivity, but its temperature coefficient is large and its perovskite phase is the weak point under strong acid. The sources read here cover its phase data, microwave values and leaching behaviour. They give no thermal, mechanical or space data.
updated: '2026-10-26'
review:
  status: draft
  method: assistant
  checked_values: 12
  unreachable: 2
  caveats: 3
  note: 'Read by an AI assistant on 2026-10-26 from the pages and PDFs fetched in that run. Unreachable in that run: the American Elements calcium titanate SDS (bot challenge) and a Santa Cruz SDS (served as HTML, not a PDF). Caveats: the 2022 abstract and Table 2 disagree on relative density, the 2022 introduction and Table 3 disagree on the reference 16 tau f, and Table 3 gives no measurement frequency. The strontium titanate values are in the related block and are not in the properties list.'
sources:
  angstrom-sds:
    title: 'Angstrom Sciences: Safety Data Sheet, Calcium Titanium Oxide (CAS 12049-50-2)'
    id: Angstrom Sciences SDS, revised 07/08/15, EC 234-988-1
    url: https://angstromsciences.com/wp-content/uploads/files/SDS/Calcium%20Titanium%20Oxide.pdf
    year: 2015
    kind: datasheet
    license: supplier document, linked not reproduced
  pubchem-cto:
    title: PubChem compound record, Calcium titanate (CID 162251)
    id: CID 162251; molecular formula CaO3Ti; molecular weight 135.94
    url: https://pubchem.ncbi.nlm.nih.gov/compound/162251
    year: 2026
    kind: database
    license: public domain (NCBI)
  nist-atomic-weights:
    title: 'NIST: Atomic Weights and Isotopic Compositions for All Elements'
    id: NIST Physical Measurement Laboratory, standard atomic weight column
    url: https://physics.nist.gov/cgi-bin/Compositions/stand_alone.pl
    kind: database
    license: US government work
  jmmm-cto2022:
    title: Effect of A-site modification on structural and microwave dielectric properties of calcium titanate
    id: J. Met. Mater. Miner. 32(3), 118-125 (2022), DOI 10.55713/jmmm.v32i3.1525
    url: https://jmmm.material.chula.ac.th/index.php/jmmm/article/download/1525/1165
    year: 2022
    kind: paper
    license: journal open access, licence not checked
  blackburn2021:
    title: Influence of accessory phases and surrogate type on accelerated leaching of zirconolite wasteforms
    id: doi:10.1038/s41529-021-00171-8 (npj Materials Degradation 5, 24)
    url: https://eprints.whiterose.ac.uk/173147/9/s41529-021-00171-8.pdf
    year: 2021
    kind: paper
    license: CC BY 4.0 (repository copy)
  guennou2010:
    title: High-pressure investigations of CaTiO3 up to 60 GPa using X-ray diffraction and Raman spectroscopy
    id: arXiv:1006.4423 (Guennou, Bouvier, Krikler, Kreisel, Haumont, Garbarino)
    url: https://arxiv.org/pdf/1006.4423
    year: 2010
    kind: paper
    license: arXiv preprint, licence not checked
  usgs-mcs2026-titanium:
    title: Mineral Commodity Summaries 2026, Titanium and Titanium Dioxide
    id: USGS MCS 2026
    url: https://pubs.usgs.gov/periodicals/mcs2026/mcs2026-titanium.pdf
    year: 2026
    kind: report
    license: public domain (USGS)
  sto-surfacenet:
    title: 'SurfaceNet: Strontium titanate (SrTiO3) datasheet'
    id: SurfaceNet datasheet, strontium titanate
    url: https://surfacenet.de/files/kr_Strontium_Titanate.php
    kind: web
    license: supplier page, linked not reproduced
  sam-sto-msds:
    title: 'Stanford Advanced Materials: Material Safety Data Sheet, Strontium titanate (SrTiO3)'
    id: SAM strontium titanate MSDS, version 2.0, 5 September 2012, CAS 12060-59-2
    url: https://www.sputtertargets.net/Public/pdf/strontium-titanate-msds.pdf
    year: 2012
    kind: datasheet
    license: supplier document, linked not reproduced
  pubchem-sto:
    title: PubChem compound record, Strontium titanium oxide (SrTiO3, CID 82899)
    id: CID 82899; molecular formula O3SrTi; molecular weight 183.49
    url: https://pubchem.ncbi.nlm.nih.gov/compound/82899
    year: 2026
    kind: database
    license: public domain (NCBI)
  wikipedia-cto:
    title: 'Wikipedia: Calcium titanate (used for the history of the name only)'
    id: English Wikipedia article, Calcium titanate
    url: https://en.wikipedia.org/wiki/Calcium_titanate
    year: 2026
    kind: web
    license: CC BY-SA 4.0
license: CC-BY-4.0