Strontium

Atomic Number: 38
Atomic Weight: 87.62
Phase at Room Temperature: Solid
Group Name: Alkaline Earth Metal
Period Number: 5 Group Number: 2
Named for the town of Strontian, Scotland.
Strontium is pronounced as STRON-she-em.

Strontium vigoursly reacts with air and so occurs naturally only in compounds with other elements, as in the minerals strontianite, celestite, etc. Strontium is softer than calcium and decomposes water more vigorously. Freshly cut strontium has a silvery appearance, but rapidly turns a yellowish colour with the formation of the oxide. The finely divided metal ignites spontaneously in air. Volatile strontium salts impart an excellent crimson colour to flames, and these salts are used in pyrotechnics. Strontium titanate has an extremely high refractive index and an optical dispersion greater than that of diamond, making it useful in a variety of optics applications.

The human body absorbs strontium as if it were calcium. So in its application as 89Sr, an active ingredient a radiopharmaceutical used for bone pain secondary to metastatic prostate cancer, the strontium acts like calcium and is preferentially incorporated into bone at sites of increased osteogenesis. This localization focuses the radiation exposure on the cancerous lesion. Other applications include: Strontium chloride which is sometimes used in toothpastes for sensitive teeth and strontium oxide which is used to improve the quality of some pottery glazes. In its pure form strontium is extremely reactive with air and spontaneously combusts. It is therefore considered to be a fire hazard.