strontium

Strontium

Name:Strontium

Symbol:Sr

Atomic Number:38

Atomic Mass:87.62

Density: 33.94 g/cm^3

Melting Point:777 �C

Boiling Point:1382 �C

Group Number:2

Group Name:Alkaline Earth Metals

Standard State:Solid at room temperature

Color:silvery white

Classification:Metallic

Strontium does not occur as the free element. Strontium is softer than

calcium and decomposes water more vigorously. Freshly cut strontium

has a silvery appearance, but rapidly turns a yellowish color with the

formation of the oxide. The finely divided metal ignites spontaneously

in air. Volatile strontium salts impart an excellent crimson color to

flames, and these salts are used in pyrotechnics.

The picture shows the colour arising from adding strontium sulphate

salt to a burning mixture of potassium chlorate and sucrose.

The picture above shows the color arising from adding strontium

sulphate salt (SrSO[4]) to a burning mixture of potassium chlorate and

sucrose. Do not attempt this reaction unless are a professionally

qualified chemist and you have carried out a legally satisfactory

hazard assessment.

Strontium-90 (^90Sr) has a half-life of 28 years. It is a product of

nuclear fallout and presents a major health problem. Strontium

titanate is an interesting optical material as it has an extremely

high refractive index and an optical dispersion greater than that of

diamond. It has been used as a gemstone, but it is very soft.

Isolation

Strontium metal is available commercially and there is no need to make

it in the laboratory. Commercially it is made on small scale by the

electrolysis of molten strontium chloride, SrCl[2].

cathode: Sr^2+(l) + 2e^- -> Sr anode: Cl^-(l) -> ^1/[2]Cl[2] (g) + e^-

Strontium metal can also be isolated from the reduction of strontium

oxide, SrO, with aluminum.