The key facts Greetings, and welcome to the third installment of a regular feature on the Radleys blog – the Element of the Month. To choose our element of the month, we used a random number generator to produce a figure between 1 and 118 – the current number of elements in the periodic table. This month, we drew the number 83, which makes bismuth our third element of the month. Bismuth – The Key Facts Bismuth is a chemical element with symbol Bi and atomic number 83. It is one of the few elements whose liquid state has a higher density than its solid state. Almost twice as abundant as gold in the earth’s crust, bismuth is a brittle metal, silvery white in colour when it is freshly produced, and often seen with a pink tinge due to surface oxidation once in contact with air. Bismuth crystals are truly stunning, as the varying layers of oxidation disturb the light wavelengths that reflect on its surface, creating a veritable rainbow of colours. Although rather alien-looking, you may be surprised to know that you may, in fact, have either ingested, worn, or used bismuth before. Read on to find out more… Fascinating Facts About Bismuth 1. Bismuth was one of the first metals to be discovered, although often confused with lead or tin, with which it shares similar physical properties. It wasn’t until 1753 that Claude Geoffroy identified it as a separate element. 2. Bismuth is the single most naturally diamagnetic element or metal: this can be tested out at home with this simple home science project that enables you to levitate a magnet: 3. Bismuth crystals grow in oddly beautiful, staircase-shaped formations as the result of a greater growth rate on the outside edges than on the inside edges. 4. With a low melting point of just above 271 degrees Celsius, bismuth crystals can be grown at home on the stove: 5. Bismuth was long considered to be the heaviest stable element in the periodic table. However, in 2003, scientists discovered that it is weakly radioactive: bismuth-209 (its only primordial isotope) has a half-life more than a billion times longer than the estimated age of the universe. 6. With extremely low levels of toxicity for a heavy metal, bismuth is used in a number of pharmaceuticals, such as antidiarrhoeal medicines like Pepto-Bismol. It can also be used to treat eye infections (Bibrocathol) or peptic ulcers (with a combination of bismuth subsalicylate and bismuth subcitrate) 7. In ancient Egypt, a bismuth compound named bismoclite was used for cosmetic purposes and, in fact, still is in certain eye shadows, hair sprays, and nail polishes, as its crystal form resembles nacre of pearl. 8. Due to its unusually low toxicity levels, bismuth has increasingly been used as a replacement for lead in pencils and bullets. So, that’s bismuth – a substance that’s denser as a liquid than as a solid and our third Element of the Month. If you want to learn more about Bismuth, click here to watch a short video by The University of Nottingham. Come back next month, when we’ll be raving about rhodium.