Crystallography365

Blogging a crystal structure a day in 2014

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Helen Maynard-Casely

The crystal structure rainbow – Glowing in UV, Andersonite

Just to extend on our theme for this week a little – how about a crystal structure that glows in UV light? It's also one of the minerals in this post we mentioned yesterday, so it ties up things very nicely!

What does it look like?

Image generated by the VESTA (Visualisation for Electronic and STructual analysis) software http://jp-minerals.org/vesta/en/

Image generated by the VESTA (Visualisation for Electronic and STructual analysis) software http://jp-minerals.org/vesta/en/

What is it?

Andersonite is a rare Uranium carbonate mineral that was first found in Arizona in the US. It's fluorescent and will glow a yellowy-green under UV light. As you can see hinted in the picture, its crystal structure is quite complex – with units of carbonate (CO3, brown carbon atoms surrounded by red oxygen atoms), sodium (yellow atoms) and calcium (blue) atoms which all surround the uranium (green) atoms. Because of the way uranium atoms are made up, they can bond with up to 6 other atoms at a time. This makes for quite a variety of minerals that it can form.

Where did the structure come from?

The crystal structure of Andersonite was determined in 1981, and it is #907645 in the Crystallography Open Database.

Tags: mineral   colours   ultraviolet   uranium