Стронций фторид

Химические свойства

Strontium fluoride, also called strontium difluoride and strontium(II) fluoride, is a fluoride of strontium. It is a stable brittle white crystalline solid. It forms face-centered cubic crystals, with structure of calcium fluoride. It is almost insoluble in water. Strontium fluoride is prepared by reaction of strontium chloride with fluorine gas, by action of hydrofluoric acid on strontium carbonate, or by addition of potassium chloride to strontium chloride solution. It irritates eyes and skin, and is harmful when inhaled or ingested.

Физические свойства

Strontium fluoride, SrF2, also called "strontium difluoride" and "strontium (II) fluoride", is a stable, brittle, white crystalline solid with a melting point of 1477°C and a boiling point of 2460°C. Its molecular weight is 125.62 g/mol. Its density is 4.24 g/cm3. Its melting point has also been given as 1463°C and a boiling point of 2489°C. It is virtually insoluble since its solubility in water is 0.00012 g/100 ml of water at 18°C.
SrF2 is almost insoluble in water (its KSP value is approximately 4.33×10⁹ at 25°C. It irritates eyes and skin, and is harmful when inhaled or ingested.

Использование

Strontium fluoride is transparent to light in the wavelengths from the vacuum UV (150 nm) to the near IR (11 mm). Its optical properties are intermediate to CaF2 and BaF2. Strontium fluoride is used as an optical material for a small range of special applications, for example, as an optical coating on lenses and also as a thermoluminescent dosimeter crystal. Another use is as a carrier of the ⁹⁰Sr radioisotope in thermoelectric generators. SrF2 is also used as a single crystal for lasers.

Подготовка

Strontium fluoride is synthesized by the fluorination of strontium dichloride, or by action of hydrofluoric acid on strontium carbonate:
SrCl2 (aq)＋ F2 (gas)→SrF2 (solid)＋ Cl2 (gas)
SrCO3＋ 2HF→SrF2＋ CO2＋H2O
Note that the first reaction depends upon the insolubility of SrF2 in water. Strontium fluoride is a water-insoluble source for use in oxygen-sensitive applications, such as metal production since it in nonhygroscopic.

Опасность

Toxic material.

Профиль безопасности

Moderately toxic by intravenous route. Mildly toxic by ingestion. When heated to decomposition it emits toxic fumes of F-. See also FLUORIDES and STRONTIUM COMPOUNDS.