Strontium

Strontium is a chemical element; it has symbol Sr and atomic number 38. An alkaline earth metal, it is a soft silver-white yellowish metallic element that is highly chemically reactive. The metal forms a dark oxide layer when it is exposed to air. Strontium has physical and chemical properties similar to those of its two vertical neighbors in the periodic table, calcium and barium. It occurs naturally mainly in the minerals celestine and strontianite, and is mostly mined from these.

radiometric dating technique for rocks and minerals based on the quantities of specific isotopes of rubidium (⁸⁷Rb) and strontium (⁸⁷Sr, ⁸⁶Sr)

2001, country of Georgia, 3 injured, 1 dead

right|thumb|Diagram of the soviet radioisotopic thermoelectric generator "Beta-M". Black: Framework Blue: Outer radiation protection Yellow: Heat isolation Orange: Inner radiation protection (Tungsten) Red: Radionuclide heat source (Strontium-90) Pink: Thermoelectric unit Mounted above the assembly are fins for cooling, outlined in black.|360x360px