File:Strontium (38 Sr).jpg

Summary
Strontium is very similar to calcium, but it is more heavy and reactive. For this metal and its compounds, only very few and special applications exist. Strontium salts are used to make red fireworks. Strontium is notorious for the radioactive 90Sr, which is produced in nuclear power plants as well as in atomic explosions like that in Chernobyl and from atomic bombs. This has a half-life of 29 years. It is build into bones like calcium and there causes cancer. https://commons.wikimedia.org/wiki/File:Strontium_(38_Sr).jpg