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Ammonium hexachloroplatinate

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 Edit this at Wikidata
EC Number
  • 240-973-0
UNII
  • InChI=1S/6ClH.2H3N.Pt/h6*1H;2*1H3;/q;;;;;;;;+4/p-4 checkY
    Key: PCCGQTHFYHJATL-UHFFFAOYSA-J checkY
  • InChI=1/6ClH.2H3N.Pt/h6*1H;2*1H3;/q;;;;;;;;+4/p-4/rCl6Pt.2H3N/c1-7(2,3,4,5)6;;/h;2*1H3/q-2;;/p+2
    Key: PCCGQTHFYHJATL-WPAIPAOFAY
  • [NH4+].[NH4+].Cl[Pt-2](Cl)(Cl)(Cl)(Cl)Cl
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 labelling:
GHS05: CorrosiveGHS06: ToxicGHS07: Exclamation markGHS08: Health hazard
Danger
H290, H301, H317, H318, H334
P234, P261, P264, P270, P272, P280, P285, P301+P310, P302+P352, P304+P341, P305+P351+P338, P310, P321, P330, P333+P313, P342+P311, 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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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.

Preparation and structure

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 reactions

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]

Ammonium hexachloroplatinate decomposes to yield platinum sponge when heated to high temperatures:[2][5]

3(NH4)2PtCl6 → 3Pt(s) + 2NH4Cl(g) + 16HCl(g) + 2N2(g)

Safety

Dust containing ammonium hexachloroplatinate can be highly allergenic. "Symptoms range from irritation of skin and mucous membranes to life-threatening attacks of asthma."[6]


References

  1. ^ "ammonium hexachloroplatinate(IV)". Chemister.ru. 2007-03-19. Retrieved 2014-06-03.
  2. ^ a b c George B. Kauffman (1967). "Ammonium Hexachloroplatinate(IV)". Inorganic Syntheses. Vol. 9. pp. 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
  5. ^ Rochow, Eugene George (1977). Modern Descriptive Chemistry. W. B. Saunders Company. p. 202. ISBN 9780721676289.
  6. ^ Renner, Hermann; Schlamp, Günther; Kleinwächter, Ingo; Drost, Ernst; Lüschow, Hans Martin; Tews, Peter; Panster, Peter; Diehl, Manfred; Lang, Jutta; Kreuzer, Thomas; Knödler, Alfons; Starz, Karl Anton; Dermann, Klaus; Rothaut, Josef; Drieselmann, Ralf; Peter, Catrin; Schiele, Rainer (2001). "Platinum Group Metals and Compounds". Ullmann's Encyclopedia of Industrial Chemistry. doi:10.1002/14356007.a21_075. ISBN 3527306730.
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