Element number 8 in our International Year of the Periodic Table series is oxygen. Oxygen is a paramagnetic gas which is essential for respiration of living things, and also finds use as a rocket fuel.

Oxygen is a magnetic gas, though this isn’t something that’s demonstrable in the gaseous state. However, if oxygen is cooled until it forms pale blue liquid oxygen, it can be shown to be attracted by a magnet.

Along with nitrogen, oxygen is the other gas that makes up the bulk of the air we breathe, accounting for 21%. This is quite a handy figure, as below 17% breathing can become difficult, and above 25% flammable organic compounds start to catch fire rather easily. Oxygen atoms also make up 65% of the mass of the human body, largely found as part of water molecules.

Liquid oxygen is used as an oxidiser in some rocket propellants, often with liquid hydrogen or kerosene. It’s not the biggest commercial use of oxygen gas, however – that title goes to smelting of iron ore into steel.

Remember, you can keep track of all of the previous entries in this series on the site here, or on the Royal Society of Chemistry’s dedicated page.

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