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| Names | |
|---|---|
| IUPAC name Platinum(II) chloride | |
| Other names Platinous chloride | |
| Identifiers | |
3D model (JSmol) |
|
| ChEBI | |
| ChemSpider |
|
| ECHA InfoCard | 100.030.019 |
| EC Number |
|
| 1744965 | |
| UNII | |
| |
| |
| Properties | |
| PtCl2 | |
| Molar mass | 265.99 g/mol |
| Appearance | dark brown powder |
| Density | 6.05 g/cm3, solid |
| Melting point | 581 °C (1,078 °F; 854 K) |
| Boiling point | decomposes |
| insoluble | |
| Solubility | insoluble inalcohol,ether soluble inHCl,ammonia |
| −54.0·10−6 cm3/mol | |
| Structure | |
| hexagonal | |
| Hazards | |
| GHS labelling:[1] | |
   | |
| Danger | |
| H314,H315,H317,H319,H334 | |
| P260,P261,P264,P272,P280,P285,P301+P330+P331,P302+P352,P303+P361+P353,P304+P340,P304+P341,P305+P351+P338,P310,P321,P332+P313,P333+P313,P337+P313,P342+P311,P362,P363,P405,P501 | |
| Lethal dose or concentration (LD, LC): | |
LD50 (median dose) | 3423 mg/kg (rat, oral) |
| Related compounds | |
Otheranions | Platinum(II) bromide Platinum(II) sulfide |
Othercations | Palladium(II) chloride |
Related compounds | Platinum(IV) chloride |
Except where otherwise noted, data are given for materials in theirstandard state (at 25 °C [77 °F], 100 kPa). | |
Platinum(II) chloride describes theinorganic compounds with the formulaPtCl2. They are precursor used in the preparation of other platinum compounds. Platinum(II) chloride exists in two crystalline forms (polymorphs), but the main properties are somewhat similar: dark brown, insoluble in water,diamagnetic, and odorless.
The structures of PtCl2 andPdCl2 are similar. These dichlorides exist in both polymeric, or "α", and hexameric, or "β" structures. The β form converts to the α form at 500 °C. In the β form, the Pt-Pt distances are 3.32–3.40 Å, indicative of some bonding between the pairs of metals. In both forms of PtCl2, each Pt center is four-coordinate, being surrounded by four chlorideligands. Complementarily, each Cl center is two-coordinate, being connected to two platinum atoms.[2] The structure of α-PtCl2 is reported to be disordered and contain edge- and/or corner-sharing square-planar PtCl4 units.[3]
β-PtCl2 is prepared by heatingchloroplatinic acid to 350 °C in air.[4]
This method is convenient since the chloroplatinic acid is generated readily from Pt metal. Aqueous solutions of H2PtCl6 can also be reduced withhydrazinium salts, but this method is more laborious than the thermal route of Kerr and Schweizer.
Although PtCl2 can form when platinum metal contacts hotchlorine gas, this process suffers from over-chlorination to givePtCl4.Berzelius and later Wöhler and Streicher showed that upon heating to 450 °C, this Pt(IV) compound decomposes to the Pt(II) derivative:[5][6]
Transformations such as this are "driven" byentropy, the free energy gained upon the release of a gaseous product from a solid. Upon heating to still higher temperatures, PtCl2 releases more chlorine to give metallic Pt. This conversion is the basis of thegravimetric assay of the purity of the PtCl2 product.
Most reactions of PtCl2 proceed via treatment with ligands (L) to give molecular derivatives. These transformations entail depolymerization via cleavage of Pt-Cl-Pt linkages:
Addition of ammonia gives initially "PtCl2(NH3)2", "Magnus's green salt", also described as [Pt(NH3)4][PtCl4].
Manycomplexes have been described, the following are illustrative:[7]
Several of these compounds are of interest inhomogeneous catalysis in the service oforganic synthesis or as anti-cancer drugs.
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