Strontium

About Strontium

Strontium is the alkaline-earth metal that takes its name from Strontian, a small village in the Scottish Highlands where it was first identified in lead-mine ore. Chemically it sits between calcium and barium in group 2 and behaves like a heavier calcium — it forms Sr²⁺ exclusively, oxidises rapidly in air to a yellowish coating, and the metal must be stored under mineral oil. Pyrotechnicians know it for the deep crimson it adds to flames: strontium nitrate Sr(NO₃)₂ and strontium carbonate are the standard red colourants in fireworks, road flares, and tracer rounds, with peak emission lines around 605-682 nm. The natural element is a mix of four stable isotopes (⁸⁴Sr, ⁸⁶Sr, ⁸⁷Sr, ⁸⁸Sr); the ⁸⁷Sr/⁸⁶Sr ratio is one of the workhorse provenance tracers in archaeology and food forensics, because it's set by the local bedrock you grew up drinking water from. ⁹⁰Sr is the notorious one — a high-yield fission product with a 28.8-year half-life and a β-decay daughter (⁹⁰Y) that adds to the dose. Because Sr²⁺ mimics Ca²⁺ in bone metabolism, ⁹⁰Sr from atmospheric tests of the 1950s ended up in baby teeth worldwide, which is partly what got the test ban moving. Strontium aluminate doped with europium is the long-glow phosphor in modern luminous paint.