Palladium(II) iodide is an inorganic compound of palladium and iodine. It is commercially available, though less common than palladium(II) chloride, the usual entry point to palladium chemistry. Three polymorphs are known.[2]
Preparation
Palladium(II) iodide can be obtained by treating a dilute solution of palladium in nitric acid with sodium iodide at 80 °C.[2]
The high-temperature polymorph α-palladium(II) iodide can be produced by reaction of the elements at temperature above 600 °C. The γ-modification is produced as an almost amorphous powder by addition of iodide salts to aqueous H2PdCl4 solution . When heated in dilute hydrogen iodide solution, this polymorph transforms into the β phase at around 140 °C.[3]
Reactions and uses
Palladium(II) iodide is insoluble in water. It reacts with iodide giving PdI42−anion:
Historically, the quantity of palladium in a solution may be determined gravimetrically by precipitation as palladium(II) iodide.[5]
Crystallography
Palladium(II) iodide is an almost X-ray amorphous black powder. The α-modification has an orthorhombic crystal structure with the space groupPnmn(space group no. 58, position 5).[6]
^Beamish, F. E.; Dale, J. (1938). "Determination of Palladium by Means of Potassium Iodide". Industrial & Engineering Chemistry Analytical Edition. 10 (12): 697. doi:10.1021/ac50128a015.