Barium orthotitanate is the

inorganic compound An inorganic compound is typically a chemical compound that lacks carbon–hydrogen bonds⁠that is, a compound that is not an organic compound. The study of inorganic compounds is a subfield of chemistry known as ''inorganic chemistry''. Inorgan ...

with the

chemical formula A chemical formula is a way of presenting information about the chemical proportions of atoms that constitute a particular chemical compound or molecule, using chemical element symbols, numbers, and sometimes also other symbols, such as pare ...

Ba₂TiO₄. It is a colourless solid that is of interest because of its relationship to

barium titanate Barium titanate (BTO) is an inorganic compound with chemical formula BaTiO3. It is the barium salt of metatitanic acid. Barium titanate appears white as a powder and is transparent when prepared as large crystals. It is a Ferroelectricity, ferroe ...

, 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 Sintering or frittage is the process of compacting and forming a solid mass of material by pressure or heat without melting it to the point of liquefaction. Sintering happens as part of a manufacturing process used with metals, ceramics, plas ...

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 A thin film is a layer of materials ranging from fractions of a nanometer ( monolayer) to several micrometers in thickness. The controlled synthesis of materials as thin films (a process referred to as deposition) is a fundamental step in many ...

with

chemical vapor deposition Chemical vapor deposition (CVD) is a vacuum deposition method used to produce high-quality, and high-performance, solid materials. The process is often used in the semiconductor industry to produce thin films. In typical CVD, the wafer (electro ...

Properties

* Room temperature

entropy Entropy is a scientific concept, most commonly associated with states of disorder, randomness, or uncertainty. The term and the concept are used in diverse fields, from classical thermodynamics, where it was first recognized, to the micros ...

– 47.0 cal/deg. mol *

Dielectric constant The relative permittivity (in older texts, dielectric constant) is the permittivity of a material expressed as a ratio with the electric permittivity of a vacuum. A dielectric is an insulating material, and the dielectric constant of an insul ...

– 20 (at 100 kHz) * It is

hygroscopic Hygroscopy is the phenomenon of attracting and holding water molecules via either absorption (chemistry), absorption or adsorption from the surrounding Natural environment, environment, which is usually at normal or room temperature. If water mol ...

and decomposes with swelling in moist air. Barium orthotitanate can remove up to 99.9% of from a high-temperature gas stream by the reaction: : + → +

References

{{Titanates Titanates Barium compounds