STRONTIUM SELENIDE

Описание

Strontium selenide has the molecular formula of SrSe and the molecular weight of 166.5852 g/mol. It is a white cubic crystal whose CAS number is 1315-07-7. Its melting point is 1605°C and its density is 4.54 g/cm³. It reacts with water and so cannot be prepared by an aqueous precipitation method. It can be prepared by the reaction of the oxide with Se metal:
2SrO+ Se+ Heat ? SrSe+ SeO2
It can also be prepared by reducing the selenate with hydrogen gas:
SrSeO4 + 4H2 + heat ? SrSe+ 4H2O
Strontium selenide and barium selenide both have a simple cubic structure, with cube edges equal to 3.117? and 3.308 ?, respectively. In the case of SrSe, the ions at the corners are Sr⁺⁺ and Se^--。

Химические свойства

white cub; -20 mesh with 99.5% purity [CER91] [CRC10]

Физические свойства

Phosphors can be categorized in accordance with their behavior as fluorescent, phosphorescent or stimulable. As used in this disclosure, such categories should be understood as based upon the predominant behavior of the phosphor at about room temperature, i.e at about 20°C.
? A “stimulable” phosphor is one that, at room temperature, stores energy absorbed upon exposure to excitation by electromagnetic radiation and releases the predominant portion of the stored energy upon exposure to stimulating electromagnetic radiation.
? A phosphorescent phosphor at room temperature will store absorbed energy for an appreciable time but will release the predominant portion of the stored energy spontaneously.
? A fluorescent phosphor will release the predominant portion of the absorbed energy as emission radiant energy substantially simultaneously with exposure to the exciting radiant energy.

Использование

The major usage of SrSe has been as an infrared stimulable phosphor. Photoluminescent materials useful for detection of infrared light are prepared using a base material, such as SrSe. Up to three dopants, Sm3+, cerium, Ce³⁺ and Eu²⁺ compounds are used for the purpose of providing electron traps. The base material can be a combination of alkaline earth metal selenides such as strontium selenide, calcium selenide, or a mixture of these. Luminescence is a long known phenomenon of nature reaching back very far in history. Recorded observations reach back to the last century. Seeback and Becquerel observed momentary visible afterglow in certain materials.

Синтез

Pure SrSe is best obtainedfrom the selenite by high-temperature reduction with NH3.
SrSeO3 + 2NH3 = SrSe + 3 H2O + N2