Platinum(IV) iodide

Platinum(IV) iodide is a inorganic compound with the formula PtI4. it is a dark brown diamagnetic solid and is one of several binary iodides of platinum.

Preparation
Platinum(IV) iodide can be prepared from the effect of iodine on platinum:
 * Pt + 2I2 -> PtI4

It can also be obtained from the decomposition of hydrogen hexaiodoplatinate(IV) at 80 °C:
 * H2[PtI6] -> PtI4 + 2HI

Physical properties
Platinum(IV) iodide forms dark brown crystals of several modifications:


 * α-PtI4, rhombic crystal system, spatial group P bca, cell parameters a = 1.290 nm, b = 1.564 nm, c = 0.690 nm, Z = 8;


 * β-PtI4, cubic crystal system, spatial group P m3m, cell parameters a = 0.56 nm, Z = 1;


 * γ-PtI4, tetragonal crystal system, spatial group I 41/a, cell parameters a = 0.677 nm, c = 3.110 nm, Z = 8.

Platinum(IV) iodide decomposes in water. It is also soluble in ethanol, acetone, alkali, HI, KI, liquid NH3.

Chemical properties
It decomposes when heated:
 * PtI4 -> Pt + 2I2

When dissolved in hydroiodic acid, platinum(IV) iodide forms hydrogen hexaiodoplatinate(IV):
 * PtI4 + 2HI -> H2[PtI6]