Barium orthotitanate is the
inorganic compound
In chemistry, an inorganic compound is typically a chemical compound that lacks carbon–hydrogen bonds, that is, a compound that is not an organic compound. The study of inorganic compounds is a subfield of chemistry known as '' inorganic chemist ...
with the
chemical formula
In chemistry, 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, ...
Ba
2TiO
4. 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. Barium titanate appears white as a powder and is transparent when prepared as large crystals. It is a Ferroelectricity, ferroelectric, Pyroelectricity, pyroelectric, and ...
, a useful
electroceramic Electroceramics is a class of ceramic materials used primarily for their electrical properties.
While ceramics have traditionally been admired and used for their mechanical, thermal and chemical stability, their unique electrical, optical and magn ...
.
Structure
![Beta-Barium Orthotitanate crystal structure](https://upload.wikimedia.org/wikipedia/commons/3/39/Beta-Barium_Orthotitanate_crystal_structure.png)
The solid has two known phases: a low-temperature (β) phase with ''P''2
1/''n'' symmetry
and a high-temperature (α′) phase with ''P''2
1''nb'' symmetry. The structure of Ba
2TiO
4 is unusual among the
titanate In chemistry, titanate usually refers to inorganic compounds composed of titanium oxides.
Together with niobate, titanate salts form the Perovskite group.
In some cases, the term is used more generally for any titanium-containing anion, e.g. iC ...
s 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
Clinker nodules produced by 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 ...
BaCO
3 and TiO
2. Another method of preparation is heating pellets of
Ba(OH)2 and TiO
2.
Additionally, there are polymer
precursor
Precursor or Precursors may refer to:
*Precursor (religion), a forerunner, predecessor
** The Precursor, John the Baptist
Science and technology
* Precursor (bird), a hypothesized genus of fossil birds that was composed of fossilized parts of unr ...
,
sol-gel and
reverse micellar routes to Ba
2TiO
4 synthesis.
Ba
2TiO
4 has also been successfully grown as a
thin film
A thin film is a layer of material 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 ap ...
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 (substra ...
.
Properties
* Room temperature
entropy
Entropy is a scientific concept, as well as a measurable physical property, that is most commonly associated with a state of disorder, randomness, or uncertainty. The term and the concept are used in diverse fields, from classical thermodynam ...
- 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 insulat ...
- 20 (at 100 kHz)
* It is
hygroscopic
Hygroscopy is the phenomenon of attracting and holding water molecules via either absorption or adsorption from the surrounding environment, which is usually at normal or room temperature. If water molecules become suspended among the substance ...
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
{{Titanium compounds
Titanates
Barium compounds