View source for Strontium

[[File:Sr,38.jpg|thumb|[[Granule]]s of strontium in a glass tube]]
[[File:Stronzianite 01.png|thumb|A piece of [[strontianite]]]]

'''Strontium''' is a [[chemical element]]. It has the chemical symbol '''Sr'''. It has the [[atomic number]] 38. It is a [[metal]]. The color of the metal is silver-white or yellow-silver. The metal is [[soft|soft]], and highly [[reactivity (chemistry)|reactive]] chemically. 

In chemistry it is placed in a group of metal elements named the [[alkaline earth metal]]s. Strontium has a high [[chemical reactivity]]. The metal turns yellow when exposed to air. Strontium has properties similar to those of its two vertical neighbors in the [[periodic table]], [[calcium]] and [[barium]]. 

It is found naturally in the [[mineral]]s [[celestite]] and [[strontianite]]. The <sup>90</sup>Sr [[isotope]] is present in [[radioactive]] [[nuclear fallout|fallout]] and has a [[Half-life (element)|half-life]] of 28.9 years.

Strontium forms salts which make a red flame when they burn. They are used in flares for signalling the position of survivors or shipwrecks and to make the red color in fireworks.
It is named after the village of Strontian, Scotland.  

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== Strontium Media ==
<gallery widths='160px' heights='100%' mode='traditional' caption=''>
File:Strontium 1.jpg|Oxidized [[Dendrite (crystal)|dendritic]] strontium

File:FlammenfärbungSr.png|[[Flame test]] for strontium

File:Celestine Poland.jpg|The mineral celestine ({{chem2|SrSO4}})

File:Monitor.arp.jpg|Most of the world's production of strontium used to be consumed in the production of cathode-ray tube (CRT) displays. The glass contained strontium and barium oxide to block X-rays.

File:Ignis Brunensis 2010-05-22 (5).jpg|Strontium salts are added to fireworks in order to create red colors.

File:Soviet RTG.jpg|RTGs from Soviet-era lighthouses
</gallery>
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[[Category:Alkaline earth metals]]