Calcium titanate is an inorganic compound with the chemical formula CaTiO3. As a mineral, it is called perovskite, named after Russian mineralogist, L. A. Perovski (1792-1856). It is a colourless, diamagnetic solid, although the mineral is often coloured owing to impurities.
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Other names
calcium titanium oxide
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Identifiers | |
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ChemSpider | |
ECHA InfoCard | 100.031.795 |
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Properties | |
CaTiO3 | |
Molar mass | 135.943 g/mol |
Appearance | white powder |
Density | 4.1 g/cm3 |
Melting point | 1,975 °C (3,587 °F; 2,248 K) |
Boiling point | 3,000 °C (5,430 °F; 3,270 K) |
insoluble | |
Hazards | |
Lethal dose or concentration (LD, LC): | |
LD50 (median dose)
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>1200 mg/kg (oral, rat) |
Thermochemistry | |
Std molar
entropy (S⦵298) |
93.64 J/mol·K [1] |
Std enthalpy of
formation (ΔfH⦵298) |
-1660.630 kJ/mol [1] |
Gibbs free energy (ΔfG⦵)
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-1575.256 kJ/mol [1] |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Synthesis
editCaTiO3 can be prepared by the combination of CaO and TiO2 at temperatures >1300 °C. Sol-gel processes has been used to make a more pure substance, as well as lowering the synthesis temperature. These compounds synthesized are more compressible due to the powders from the sol-gel process as well and bring it closer to its calculated density (~4.04 g/ml).[2]
Structure
editCalcium titanate is obtained as orthorhombic crystals, more specifically perovskite structure.[3] In this motif, the Ti(IV) centers are octahedral and the Ca2 centers occupy a cage of 12 oxygen centres. Many useful materials adopt related structures, e.g. barium titanate or variations of the structure, e.g. yttrium barium copper oxide.[citation needed]
Applications
editCalcium titanate has relatively little value except as one of the ores of titanium, together with several others. It is reduced to give titanium metal or ferrotitanium alloys.[4]
See also
editReferences
edit- ^ a b c Robie, R. A.; Hemmingway, B. S.; Fisher, J. R. (1978). "Thermodynamic properties of minerals and related substances at 298.15 K and 1 bar pressure and at higher temperature" (PDF). Geol. Surv. Bull.: 1452. Bibcode:1978BUSGS.....1452R. doi:10.3133/b1452.
- ^ Dunn, Bruce; Zink, Jeffrey I. (September 2007). "Sol–Gel Chemistry and Materials". Accounts of Chemical Research. 40 (9): 729. doi:10.1021/ar700178b. PMID 17874844.
- ^ Buttner, R. H.; Maslen, E. N. (1 October 1992). "Electron difference density and structural parameters in CaTiO3". Acta Crystallographica Section B. 48 (5): 644–649. doi:10.1107/S0108768192004592.
- ^ Sibum, Heinz; Güther, Volker; Roidl, Oskar; Habashi, Fathi; Wolf, Hans Uwe (2000). "Titanium, Titanium Alloys, and Titanium Compounds". Ullmann's Encyclopedia of Industrial Chemistry. doi:10.1002/14356007.a27_095. ISBN 978-3-527-30673-2.