The alpha form of solid polonium.
Polonium is a rare radioactive metalloid. It is chemical element 84 on the periodic table and its symbol is Po. It was discovered in 1898 by Marie and Pierre Curie.
Polonium is highly unstable, radioactive and toxic. This makes it difficult to handle. It can be dangerous, even in very small amounts. One gram of Po will self-heat to a temperature of about 500 °C (932 °F). It also vaporizes easily.
Polonium has 33 isotopes, and all of them are radioactive. It is a very rare element in nature because of its short half-life. It is a breakdown product of uranium, so it is found in uranium ores.
The former Russian secret service agent Alexander Litvinenko was murdered by having a tiny amount of polonium put into a drink.