Bismuth is extremely weakly radioactive.
Pure bismuth is a soft metal and is brittle when impure. Stable at room temperature. The main ores are bismuthite (Bi2S3) and bismuth ocher (Bi2o5). Liquid bismuth expands when it solidifies.
It is brittle and has poor electrical and thermal conductivity. Bismuth selenide and telluride have semiconductor properties.
Bismuth metal is a metal with silvery white (pink) to light yellow luster. It is brittle and easily pulverized. At room temperature, bismuth does not react with oxygen or water and is stable in the air. .Poor electrical and thermal conductivity; Bismuth was previously considered to be the stable element with the largest relative atomic mass, but in 2003, bismuth was discovered to be weakly radioactive and can undergo alpha decay into thallium-205. Its half-life is about 1.9X10^19 years, which is 1 billion times the age of the universe.
Extended information:
Bismuth is mainly used to make fusible alloys, with a melting point ranging from 47 to 262°C. The most commonly used bismuth is composed of lead, tin, antimony, indium and other metals. The alloy is used in fire-fighting devices, automatic sprinklers, and boiler safety plugs. Once a fire breaks out, the pistons of some water pipes will "automatically" melt and spray out water.
In the fire protection and electrical industries, it is used as automatic fire extinguishing systems and electrical fuses and solders. Bismuth alloy has the property of not shrinking when solidified and is used for casting printing type and high-precision molds. Bismuth oxycarbonate and bismuth oxynitrate are used to treat skin lesions and gastrointestinal problems.
It is used to make low-melting alloys and is of special importance in fire protection and electrical safety devices. ?
It is used to detect Mn in analytical chemistry. Bismuth can be used to make low melting point alloys, which are used in automatic closers or movable type alloys.
Baidu Encyclopedia-Bismuth