Strontium titanate

Colorless crystalline powder

Fixed

5.11 g · cm -3

2080 ° C

Insoluble in water

2.394 at 620 nm

Template: Infobox chemical / molecular formula search is not possible

Strontium titanate is a chemical compound from the group of strontium titanate.

Occurrence

Strontium titanate occurs naturally in the form of the very rare and only in 1982 discovered Minerals Tausonit ( after the Russian geologists Lev Vladimirovich Tauson ) ago.

Production and representation

Strontium titanate is obtained by means of a Verneuil method from strontium carbonate and titanium dioxide.

Properties

Strontium titanate having a cubic unit cell of the perovskite type having the space group. In the center of the unit cell is the Ti4 cation on the surface centers are the O2 - anions and on the corner locations the Sr2 cations. Up to a temperature of 105 K it has a tetragonal crystal structure with space group I4/mcm. It occurs a antiferrodistortiver transition to perovskite structure. Strontium titanate has unusual physical properties. So it is the only known compound that at low temperatures ( minus 195-770 degrees C) ductile, with increasing heat ( 770-1230 degrees C) and brittle at very high temperatures ( 1230-1530 degrees C) is ductile again.

Strontium titanate single crystals exhibit persistent photoconductivity at room temperature. After exposure, the free electron concentration is increased by two orders of magnitude and remains elevated for days.

Use

Strontium titanate is used due to its high refractive index optical component, and a window in the infrared range. In Soviet radionuclide strontium titanate was used strontium isotope 90Sr with the terrestrial purposes.

An atomic lattice defects strontium titanate has the property of a semiconductor and is being tested in research as memristor.