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Ammonium hexachloroplatinate, also known as ammonium chloroplatinate, is the inorganic compound with the formula (NH4)2[PtCl6]. It is a rare example of a soluble platinum(IV) salt that is not hygroscopic. It forms intensely yellow solutions in water. In the presence of 1M NH4Cl, its solubility is only 0.0028 g/100 mL.

Ammonium hexachloroplatinate
Ammonium hexachloroplatinate
Ammonium hexachloroplatinate
Names
IUPAC name
Ammonium hexachloroplatinate(IV)
Other names
ammonium chloroplatinate
Identifiers
3D model (JSmol)
ChEBI
ChemSpider
ECHA InfoCard 100.037.233
EC Number 240-973-0
Properties
(NH4)2PtCl6
Molar mass 443.87 g/mol
Appearance yellow crystals
Odor odorless
Density 3.065 g/cm3
Melting point 380 °C (716 °F; 653 K) decomposes
0.289 g/100ml (0 °C)
0.7 g/100ml (15 °C)[1]
0.499 g/100ml (20 °C)
3.36 g/100ml (100 °C)
Hazards
GHS pictograms The corrosion pictogram in the Globally Harmonized System of Classification and Labelling of Chemicals (GHS)The skull-and-crossbones pictogram in the Globally Harmonized System of Classification and Labelling of Chemicals (GHS)The exclamation-mark pictogram in the Globally Harmonized System of Classification and Labelling of Chemicals (GHS)The health hazard pictogram in the Globally Harmonized System of Classification and Labelling of Chemicals (GHS)
GHS signal word Danger
H290, H301, H317, H318, H334
P234, P261, P264, P270, P272, P280, P285, P301+310, P302+352, P304+341, P305+351+338, P310, P321, P330, P333+313, P342+311, P363, P390, P404, P405, P501
Lethal dose or concentration (LD, LC):
195 mg/kg rat
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Preparation and structureEdit

The compound consists of separate tetrahedral ammonium cations and octahedral [PtCl6]2− anions. It is usually generated as a fine yellow precipitate by treating a solution of hexachloroplatinic acid with a solution of an ammonium salt.[2] The complex is so poorly soluble that this step is employed in the isolation of platinum from ores and recycled residues.[3]

As analyzed by X-ray crystallography, the salt crystallizes in a cubic motif reminiscent of the fluorite structure. The [PtCl6]2− centers are octahedral. The NH4+ centers are hydrogen bonded to the chloride ligands.[4]

Uses and reactionsEdit

Ammonium hexachloroplatinate is used in platinum plating. Heating (NH4)2[PtCl6] under a stream of hydrogen at 200 °C produces platinum sponge. Treating this with chlorine gives H2[PtCl6].[2]

ReferencesEdit

  1. ^ "ammonium hexachloroplatinate(IV)". Chemister.ru. 2007-03-19. Retrieved 2014-06-03.
  2. ^ a b George B. Kauffman (1967). "Ammonium Hexachloroplatinate(IV)". Inorganic Syntheses. Inorganic Syntheses. 9: 182–185. doi:10.1002/9780470132401.ch51. ISBN 978-0-470-13240-1.
  3. ^ Cotton, S. A. Chemistry of Precious Metals, Chapman and Hall (London): 1997. ISBN 0-7514-0413-6.
  4. ^ Verde-Gómez, Y.; Alonso-Nuñez, G.; Cervantes, F.; Keer, A. "Aqueous solution reaction to synthesize ammonium hexachloroplatinate and its crystallographic and thermogravimetric characterization" Materials Letters, 2003, volume 57, p 4667-4672. doi:10.1016/S0167-577X(03)00381-1