Element 34 in our International Year of the Periodic Table series is selenium. Named after the moon, selenium compounds pop up in shampoos and are also partly responsible for the awful smell of skunk spray.
If you use a shampoo that boasts of anti-dandruff properties, then it might well contain selenium disulfide. This compound has antifungal properties and can also be used to treat certain fungal skin infections.
Selenium is the element below sulfur in the periodic table, and like sulfur its compounds can smell unpleasant (to say the least). Selenophenol has been referred to as “The biggest stinker I have run across… Imagine 6 skunks wrapped in rubber innertubes and the whole thing is set ablaze“. Meanwhile, butyl seleno-mercaptan is a key ingredient of the awful smell that skunks can produce.
Despite this selenium does have its non-odorous uses. It’s biggest use is as a glass additive. It can be added to glass to give a red colour or to remove green tints that can arise from iron impurities.
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.