5N Bismuth Bi 99.999% high pure materialPurity:4N/5NCAS#:7440-69-9Form:powder/granular/ingotBismuth is marginally radioactive and is the most naturally diamagnetic ne of the lowest values of thermal conductivity among metals. It has a high electrical resistivity. Like water, bismuth is less dense as a solid than as a liquid (it expands as it cools), a property unique for a metal.