- a bivalent, metallic element whose compounds resemble those of calcium, found in nature only in the combined state, as in strontianite: used in fireworks, flares, and tracer bullets. Symbol: Sr; atomic weight: 87.62; atomic number: 38; specific gravity: 2.6.
- a soft silvery-white element of the alkaline earth group of metals, occurring chiefly in celestite and strontianite. Its compounds burn with a crimson flame and are used in fireworks. The radioisotope strontium-90, with a half-life of 28.1 years, is used in nuclear power sources and is a hazardous nuclear fall-out product. Symbol: Sr; atomic no: 38; atomic wt: 87.62; valency: 2; relative density: 2.54; melting pt: 769°C; boiling pt: 1384°C
