CaTiO3

Calcium titanate, CaTiO3, is a calcium-containing oxide in the titanate family. It is commonly described as a perovskite-type oxide, with room-temperature crystal structure that is orthorhombic and related to the ideal cubic ABO3 perovskite. In this arrangement TiO6 octahedra form a three-dimensional framework, with Ca2+ ions occupying the larger A-site cavities. The structure is distorted from the cubic form by tilting of the octahedra, which lowers the symmetry to an orthorhombic space group such as Pbnm.

Synthesis and forms

CaTiO3 is typically prepared by solid-state reaction of calcium carbonate or calcium oxide with titanium dioxide at high temperatures (roughly 1200–1400 °C), often with prolonged calcination and controlled cooling. Alternative routes include sol-gel, citrate–gel, and hydrothermal methods. The material can be made as powders, dense ceramics, or single crystals, depending on the processing conditions.

Properties

CaTiO3 is chemically stable and exhibits a high melting point. It is a wide-bandgap insulator and tends to have moderate dielectric properties, with good thermal stability and low reactivity at elevated temperatures. It is non-magnetic. The orthorhombic distortion influences its physical properties and distinguishes it from the ideal cubic perovskite.

Applications

The material is studied as a dielectric and refractory ceramic, particularly for high-temperature capacitors and microwave dielectric applications. It also serves as a substrate or starting point for the synthesis of related titanates and for epitaxial growth of oxide films in research settings.

Occurrence

Naturally, CaTiO3 occurs as the mineral perovskite, a rare constituent in certain igneous rocks. Synthetic CaTiO3 is the common form used in research and industrial contexts.