- Chloroplatinic acid
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Chloroplatinic acid Dihydrogen hexachloroplatinate(2–)Other namesHexachloroplatinic acidIdentifiers CAS number 16941-12-1 PubChem 61859 ChemSpider 55731 UNII Q65224GJ7F EC number 241-010-7 RTECS number TP1510000 Jmol-3D images Image 1 - [H+].[H+].Cl[Pt-2](Cl)(Cl)(Cl)(Cl)Cl
Properties Molecular formula H2PtCl6 Molar mass 409.81 g/mol Appearance Reddish brown solid Density 2.431 g/cm3 Melting point 60 °C (333 K)
Boiling point decomp
Solubility in water highly soluble Structure Crystal structure Anti-fluorite. Coordination
geometryoctahedral Dipole moment 0 D Hazards MSDS External MSDS EU Index 078-009-00-4 EU classification Toxic (T)
Corrosive (C)R-phrases R25, R34, R42/43 S-phrases (S1/2), S22, S26, S36/37/39, S45 NFPA 704 Related compounds Other anions Hexachloropalladic acid Other cations Potassium hexachloroplatinate,
Ammonium hexachloroplatinate,
Rubidium hexachloroplatinate,
Caesium hexachloroplatinateacid (verify) (what is:
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Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)Infobox references Chloroplatinic acid or hexachloroplatinic acid is the chemical compound usually found as the hexahydrate with the formula H2PtCl6·(H2O)6. This is one of the most readily available soluble compounds of platinum. It is rarely obtained in the pure state. The commercial product is the oxonium salt of the hexachloroplatinate(IV) anion. Therefore, the correct formula is [H3O]2[PtCl6]·4H2O.[1][2] The related palladium compound, [H3O]2[PdCl6] is extremely unstable and has not been isolated in pure form.[3]
Contents
Production
Chloroplatinic acid is produced by dissolving platinum metal sponge in aqua regia. This reaction is rumored to produce nitrogen-containing platinum compounds, but the product is H2PtCl6. Chloroplatinic acid is brownish-red, and can be isolated by evaporating this solution to a syrup.[4]
- Pt + 4 HNO3 + 6 HCl → H2PtCl6 + 4 NO2 + 4 H2O
Alternative methods have been heavily investigated, but the older literature can be unreliable.[5]
Reactions
When hexachloroplatinic acid is heated, it decomposes through platinum(IV) chloride, platinum(II) chloride, to elemental platinum, although the reactions do not occur stepwise, cleanly:[1]
All three reactions are reversible.
Applications
Potassium determination
See also: Potassium hexachloroplatinateChloroplatinic acid was popularized for the determination of potassium. The potassium is selectively precipitated as potassium chloroplatinate. Determinations were done in 85% (v/v) alcohol solutions with excess platinate ions, and the precipitated product was weighed. Potassium could be detected for solutions as dilute as 0.02 to 0.2% (m/v).[6]
This method for determination of potassium was advantageous vs. the cobaltinitrite method used previously, since it required a single precipitation reaction.[citation needed] Today, the concentration of potassium is determined with an ion-selective electrode. These modern methods remain subject to interference.
Purification of platinum
See also: Ammonium hexachloroplatinateTreatment with an ammonium salt, such as ammonium chloride, gives ammonium hexachloroplatinate,[7] which is very insoluble in ammonium solutions. Heating the ammonium salt in hydrogen reduces it to elemental platinum. Platinum is often isolated from ores or recycled from residues thus.[8]
Catalysis
Like many platinum compounds, chloroplatinic acid is used in catalysis. This compound was first reported by John Speier and colleagues from Dow Corning Corporation to catalyze the reaction of silyl hydrides with olefins, hydrosilylation.(3) Typical of his reactions, Speier used isopropanol solutions containing trichlorosilane (SiHCl3), and methyldichlorosilane (CH3HSiCl2), with pentenes. Prior work on the addition of silanes to alkenes required radical reactions that were inefficient.[9][10] It is generally agreed that chloroplatinic acid is a catalyst precursor, and more recent discussions have considered a possible role for colloidal platinum or zero-valent complexes.[11]
Related compounds
Chloroplatinic acid prepared from aqua regia is occasionally contaminated with (NO)2PtCl6. This species is obtained by the reaction of nitrosyl chloride and Pt metal.[12]
References
- ^ a b A. E. Schweizer, G. T. Kerr (1978). "Thermal Decomposition of Hexachloroplatinic Acid". Inorg. Chem. 17 (8): 2326–2327. doi:10.1021/ic50186a067.
- ^ Holleman, Wiberg (2001). Inorganic Chemistry (First ed.). New York: Academic Press. ISBN 0123526515.
- ^ Greenwood, N.N.; Earnshaw, A. (1997). Chemistry of the Elements (Second ed.). New York: Elsevier Butterworth-Heinemann. ISBN 978-0750633659.
- ^ George B. Kauffman; Thurner, Joseph J.; Zatko, David A. (1967). "Ammonium Hexachloroplatinate(IV)". Inorganic Syntheses 9: 182–185. doi:10.1002/9780470132401.ch51.
- ^ Paul Rudnick and R. D. Cooke (1917). "The Preparation of Hydrochloroplatinic Acid by means of Hydrogen Peroxide". J. Am. Chem. Soc. 39 (4): 633–635. doi:10.1021/ja02249a011.
- ^ G. F. Smith, J. L. Gring (1933). "The Separation and Determination of the Alkali Metals Using Perchloric Acid. V. Perchloric Acid and Chloroplatinic Acid in the Determination of Small Amounts of Potassium in the Presence of Large Amounts of Sodium". J. Am. Chem. Soc. 55 (10): 3957–3961. doi:10.1021/ja01337a007.
- ^ George B. Kauffman; Thurner, Joseph J.; Zatko, David A. (1967). "Ammonium Hexachloroplatinate(IV)". Inorganic Syntheses 9: 182–185. doi:10.1002/9780470132401.ch51.
- ^ Cotton, S. A. Chemistry of Precious Metals, Chapman and Hall (London): 1997. ISBN 0-7514-0413-6.
- ^ J. L. Speier, J. A. Webster, G. H. Barnes (1957). "The Addition of Silicon Hydrides to Olefinic Double Bonds. Part II. The Use of Group VIII Metal Catalysts". J. Am. Chem. Soc. 79 (4): 974–979. doi:10.1021/ja01561a054.
- ^ John C. Saam, John L. Speier (1958). "The Addition of Silicon Hydrides to Olefinic Double Bonds. Part III. The Addition to Non-terminal Olefins in the Presence of Chloroplatinic Acid". J. Am. Chem. Soc. 80 (15): 4104–4106. doi:10.1021/ja01548a073.
- ^ L. N. Lewis, K. G. Sy, G. L. Bryant and P. E. Donahue (1991). "Platinum-catalyzed hydrosilylation of alkynes". Organometallics 10 (10): 3750–3759. doi:10.1021/om00056a055.
- ^ R. T. Moravek, G. B. Kauffman and T. Mahmood (1967). "Nitrosyl Hexachloroplatinate(IV)". Inorganic Syntheses 9: 217–220. doi:10.1002/9780470132555.ch63.
Hydrogen compounds H3AsO3 · H3AsO4 · HAt · HSO3F · HBF4 · HBr · HBrO · HBrO2 · HBrO3 · HBrO4 · HCl · HClO · HClO2 · HClO3 · HClO4 · HCN · HCNO · H2CrO4/H2Cr2O7 · H2CO3 · H2CS3 · HF · HFO · HI · HIO · HNC · HNCO · HNO · HNO3 · H2N2O2 · HNO5S · H3NSO3 · H2O · H2O2 · H2O3 · H3PO2 · H3PO3 · H3PO4 · H4P2O7 · H5P3O10 · H2PtCl6 · H2S · H2Se · H2SeO3 · H2SeO4 · H4SiO4 · H2SiF6 · H2SO3 · H2SO4 · H2SO5 · H2S2O3 · H2S2O6 · H2S2O7 · H2S2O8 · CF3SO3H · H2Te · H2TeO3 · H6TeO6 · H4TiO4 · H2Po · H3VO4 · HCo(CO)4
Categories:- Hydrogen compounds
- Coordination compounds
- Platinum compounds
- Chlorides
- Inorganic compounds
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См. также в других словарях:
chloroplatinic acid — noun An acid, HPtCl, derived from platinic chloride and hydrochloric acid, used in the analysis of amines. See Also: chloroplatinate … Wiktionary
chloroplatinic acid — | ̷ ̷ ̷ ̷+... noun Etymology: chlor + platinic : an acid H2PtCl6 obtained usually as red brown deliquescent crystals of the hexahydrate by the action of aqua regia on metallic platinum and used chiefly in analysis called also platinic chloride … Useful english dictionary
chloroplatinic acid — a red brown, crystalline, water soluble solid, H2PtCl6·6H2O, used chiefly in platinizing glass, metals, and ceramic ware. Also called platinic chloride. * * * … Universalium
chloroplatinic — /klawr euh pleuh tin ik, klohr /, adj. of or derived from chloroplatinic acid. [1835 45; CHLORO 2 + PLATINIC] * * * … Universalium
chloroplatinic — adjective Of or pertaining to chloroplatinic acid or its derivatives … Wiktionary
chloroplatinic — /klawr euh pleuh tin ik, klohr /, adj. of or derived from chloroplatinic acid. [1835 45; CHLORO 2 + PLATINIC] … Useful english dictionary
Hexafluorosilicic acid — Preferred IUPAC name Hexafluorosilicic acid Systematic name … Wikipedia
platinic acid — noun : a weak acid H2Pt(OH)6 obtained as a yellowish white precipitate by hydrolysis of chloroplatinic acid; hexa hydroxo platinic acid * * * Chem. a white, crystalline, water insoluble powder, H2PtO3, used chiefly in platinization … Useful english dictionary
hexachloroplatinic acid — ▪ chemical compound (H2PtCl6·6H2O),also called Chloroplatinic Acid, complex compound formed by dissolving platinum metal in aqua regia (a mixture of nitric and hydrochloric acids) or in hydrochloric acid that contains chlorine. It is… … Universalium
Platinum — This article is about the chemical element. For other uses, see Platinum (disambiguation). iridium ← platinum → gold Pd ↑ Pt ↓ Ds … Wikipedia