Calcium titanate
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| Names | |
|---|---|
| Other names
calcium titanium oxide | |
| Identifiers | |
| 3D model (JSmol) |
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| ChemSpider | |
| ECHA InfoCard | 100.031.795 |
| PubChem CID |
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| RTECS number | XR2568666 |
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| Properties | |
| CaTiO3 | |
| Molar mass | 135.943 g/mol |
| Appearance | white powder |
| Density | 3.98 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) |
>1200 mg/kg (oral, rat) |
| Thermochemistry | |
| Std molar entropy (S |
94.64 J/mol·K [1] |
| Std enthalpy of formation (ΔfH |
-166.0630 kJ/mol [1] |
| Gibbs free energy (ΔfG˚) |
-157.5256 kJ/mol [1] |
| Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). | |
 verify (what is  ?) | |
| Infobox references | |
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.
Synthesis
CaTiO3 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][3]
Structure
Calcium titanate is obtained as orthorhombic crystals, more specifically perovskite structure.[4] 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.
Applications
Calcium 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.[5]
See also
External links
References
- 1 2 3 R. Robie, B. Hemingway, and J. Fisher, “Thermodynamic Properties of Minerals and Related Substances at 298.15K and 1bar Pressure and at Higher Temperatures,” US Geol. Surv., vol. 1452, 1978.
- ↑ Pfaff, G. (1994). "Synthesis of calcium titanate powders by the sol-gel process". Chemistry of Materials. 6: 58. doi:10.1021/cm00037a013.
- ↑ Dunn, B.; Zink, J. I. (2007). "Sol–Gel Chemistry and Materials". Accounts of Chemical Research. 40 (9): 729. PMID 17874844. doi:10.1021/ar700178b.
- ↑ R. H. Buttner, E. N Maslen: Electron difference density and structural parameters in CaTiO3. In: Acta Crystallographica. 1992, B48, 644-649. doi:10.1107/S0108768192004592
- ↑ Heinz Sibum, Volker Günther, Oskar Roidl, Fathi Habashi, Hans Uwe Wolf, "Titanium, Titanium Alloys, and Titanium Compounds" in Ullmann's Encyclopedia of Industrial Chemistry 2005, Wiley-VCH, Weinheim. doi:10.1002/14356007.a27 095