Platinum(IV) iodide

Platinum(IV) iodide is a inorganic compound with the formula PtI₄.^[1] it is a dark brown diamagnetic solid and is one of several binary iodides of platinum.

Platinum(IV) iodide

Names
IUPAC name tetraiodoplatinum
Other names Platinum tetraiodide, platinic iodide, platinum(4+) tetraiodide
Identifiers
CAS Number	7790-46-7 Y
3D model (JSmol)	Interactive image
ChemSpider	74231
ECHA InfoCard	100.029.280
EC Number	232-207-9
PubChem CID	12978853
UNII	5TC0KR9712
CompTox Dashboard (EPA)	DTXSID30999094
InChI InChI=1S/4HI.Pt/h4*1H;/q;;;;+4/p-4 Key: RNJPWBVOCUGBGY-UHFFFAOYSA-J
SMILES I[Pt](I)(I)I
Properties
Chemical formula	I4Pt
Molar mass	702.702 g·mol−1
Appearance	brown crystals
Density	6.06 g/cm3
Melting point	130 °C (266 °F; 403 K)
Solubility in water	decomposes in water
Related compounds
Related compounds	Iridium tetraiodide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Preparation

Platinum(IV) iodide can be prepared from the effect of iodine on platinum:^[2]

Pt + 2I₂ → PtI₄

Iodide accelerates this process.^[3]

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:^[4]

• α-PtI₄, rhombic crystal system, spatial group P bca,^[5] 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.^[6]

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]