Strontium fluoride

Chemical properties

White powder. Soluble in hydrochloric acid and hydrogen fluoride; insoluble in water.

Chemical properties

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.

Physical properties

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.

The Uses of Strontium fluoride

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.

The Uses of Strontium fluoride

Substitute for other fluorides, electronic and optical applications, single crystals for lasers, hightemperature dry-film lubricants.

The Uses of Strontium fluoride

Strontium fluoride is used as an optical material transparent from vacuum ultraviolet (150 nm) to infrared (11 μm) for a small range of special applications. Its optical properties are intermediate to calcium fluoride and barium fluoride. It is also used as an optical coating on lenses.

Preparation

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.

Hazard

Toxic material.

Flammability and Explosibility

Not classified

Safety Profile

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.