Iron molecule. Computer artwork of a cubic model of a molecule of alpha-iron floating over water. Iron (Fe) atoms are depicted as spheres. This structure is known as a \body-centred cubic crystal\" in that atoms occur at each corner of the cube, with one in the centre, linked by atomic bonds. Iron is a silver- white metal capable of taking a high polish, ductile, malleable, and can be welded when hot. Three different physical forms of iron are known, with alpha- iron forming at temperatures cooler than 769 degrees Celsius. At this temperature, Fe atoms bond into the shape seen, forming an extensive lattice."