Element 16 in our International Year of the Periodic Table series is sulfur. Known since ancient times, but only confirmed as an element in the late 1700s, it’s responsible for a host of bad smells we encounter, and also finds uses in car tyres and gunpowder.

Got a whiff of a bad smell? There’s a good chance that sulfur is involved. Carbon-based compounds containing sulfur are often responsible and explain the odours of onions and garlic breath. They are also responsible for onions making you cry when you chop them). Sulfur-containing compounds such as hydrogen sulfide give flatulence its odour.

Industrially, sulfur is used in a number of processes. Its largest use is in the manufacture of sulfuric acid, which is subsequently used to make a range of fertilisers, detergents, and other useful compounds. Other industrial processes it finds use in include the vulcanization (hardening) of natural rubber for uses including car tyres. It’s also found in gunpowder, where it helps lower the ignition temperature.

Outside of industry, sulfur occurs naturally, too. It occurs in both element and compound form in volcanic areas. Emissions of sulfur dioxide from volcanic eruptions (and from the burning of fossil fuels) can cause acid rain.

Like some other elements (aluminium/aluminum, caesium/cesium), sulfur triggers a spelling debate between sulfur and sulphur. Though these are often framed as the American and English spellings respectively, etymologically there’s not much of a basis for ‘sulphur’. It actually seems that the use of sulphur in England may have been in part derived from a misunderstanding of the etymological origin of the word, and while IUPAC accepts the alternative spellings for aluminium and caesium, there’s no such allowance for sulfur.

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.