The Preparation and Some Properties of Platinum Hexafluoride 1,2

Platinum hexafluoride is the first simple hexavalent platinum compound that has been prepared. This was achieved by burning a platinum wire in a fluorine atmosphere adjacent to a cold surface with yields of up to 70%. The formula was established by chemical analyses and vapor density. A solid transition occurs at 3.0 deg , 32.5 mm pressure and the fusion point is 61.3-, 586 mm. The heat of transition is 2140 cal mole/sup -1/ and the heat of fusion is 1080 cal mole/sup -1/. The vapor pressure equations are: orthorhombic solid, log P (mnm) = --3147.6/T - 6.09 log T + 27.7758; cubic solid, log P (mm) = 2528.7/ T -4.080 log T + 20.6280; liquid, log P (mm) = --5685.8/T - 27.485 log T + boiling point of the known hexafiuorides. The heat of vaporization at the boiling point is 7060 cal mole/sup -1/. The liquid density is 3.826 g cc/sup -1/ at 64.3 deg . The density of the low temperature solid varies between 6.0-5.0 g cc/sup -1/ in the range 77-254 deg K. The vapor and liquid are red in color and the solids appear black. The molecule does not rotate freely in any of the condensed phases. Platinum hexafluoride f s the least stable and most reactive of the known hexafluorides. The use of PtF/sub 6/ as a fluorinating agent at room temperature to form BrF/sub 5/, NpF/sub 6/, and PuF/sub 6/ is described.