Strontium (Sr), chemical element, one of the alkaline-earth metals of Group 2 (IIa) of the periodic table. It is used as an ingredient in red signal flares and phosphors and is the principal health hazard in radioactive fallout. Strontium is a soft metal like lead and, when freshly cut, has a silvery lustre. It rapidly reacts in air to take on a yellowish colour; therefore, it must be protected from oxygen for storage. Continue reading from Encyclopedia Britannica
In 1787, an unusual rock which had been found in a lead mine at Strontian, Scotland, was investigated by Adair Crawford, an Edinburgh doctor. He realised it was a new mineral containing an unknown ‘earth’ which he named strontia. In 1791, another Edinburgh man, Thomas Charles Hope, made a fuller investigation of it and proved it was a new element. He also noted that it caused the flame of a candle to burn red.
Meanwhile Martin Heinrich Klaproth in Germany was working with the same mineral and he produced both strontium oxide and strontium hydroxide. Strontium metal itself was isolated in 1808 at the Royal Institution in London by Humphry Davy by means of electrolysis, using the method with which he had already isolated sodium and potassium. Continue reading from Royal Society of Chemistry
While natural strontium is harmless, one of its isotopes, Sr-90, carries a more sinister reputation: It is a dangerous byproduct of nuclear fallout. Strontium is quite common in nature — it is the 15th most abundant element in Earth's crust, according to the Minerals Education Coalition (MEC). Nearly all strontium compounds are processed from the mineral celestite. When exposed to air, it burns with a bright red flame. When combined with water, strontium gives off hydrogen gas and strontium hydroxide — a strong irritant. The first large-scale application of strontium was in the beet sugar industry just prior to World War I. Continue reading from LiveScience
