About this element
Symbol: Sr
Date of discovery: 1790
Name origin: Strontian, Scotland
Appearance: silver-white
Discoverer: Adair Crawford
Obtained from: celestite, strontianite
Melting point: 1050 K
Boiling point: 1655 K
Density[kg/m3]: 2630
Molar volume: 33.94 × 10-6 m3/mol
Protons/Electrons: 38
Neutrons: 50
Shell structure: 2,8,18,8,2
Electron configuration: [Kr]5s2
Oxidation state: 2
Crystal structure: cubic
A soft, silvery element that tarnishes in air, strontium is commonly found in nature combined with other compounds, but never as the free element. Strontium reacts vigorously with water and its salts ignite spontaneously in air, imparting a brilliant crimson color often sought after in pyrotechnics. Strontium exists in three allotropic forms with at least 16 stable isotopes. With a half-life of 29 years, 90Sr is one of the best long-lived high-energy beta emitters known. It holds promise for applications in space vehicles and remote weather stations, in which a long-lived, lightweight, nuclear, electric power source is needed.