Barium orthotitanate is the inorganic compound with the chemical formula Ba2TiO4. It is a colourless solid that is of interest because of its relationship to barium titanate, a useful electroceramic.
Structure.
The solid has two known phases: a low-temperature (β) phase with "P"21/"n" symmetry and a high-temperature (α′) phase with "P"21"nb" symmetry. The structure of Ba2TiO4 is unusual among the titanates because its titanium atoms sit in a four-oxygen tetrahedron rather than a six-oxygen octahedron.
Production.
It forms as white crystals from a melt of BaCl2, BaCO3 and TiO2 or from just sintering BaCO3 and TiO2. Another method of preparation is heating pellets of Ba(OH)2 and TiO2. Additionally, there are polymer precursor, sol-gel and reverse micellar routes to Ba2TiO4 synthesis. Ba2TiO4 has also been successfully grown as a thin film with chemical vapor deposition.
Properties.
Barium orthotitanate can remove up to 99.9% of CO2 from a high-temperature gas stream by the reaction:
Ba2TiO4 + CO2 → BaTiO3 + BaCO3