This is the molecule sulfer hexafluoride. Its formula is SF₆. The molecular mass is 146.1 amu. Its melting point is 119'C or 246'F, and its boiling point is 444.6'C or 832.3'F. Sulfur occurs in two crystalline forms, rhombic and monoclinic. In its rhomic form, SF₆'s density is 2.07 g/ml, and in its monoclinic form, it has a density of 1.96 g/ml. This molecule has an octahedral shape, otherwise known as a tetragonal bipyramid. The sulfur atom at the center of the molecule has an "expanded" valence shell with 12 shared electrons rather than the more common eight. SF₆ has six bonded pairs of electrons and no unbonded pairs of electrons. SF₆ is used for the production of rubber, chemicals used in detergents, insecticides, plant fertilizers, and non-toxic elemental sulfur. It is also used in ointments used to treat some skin diseases.