Dihydrogen hexahydroxyplatinate
[CAS# 51850-20-5]

Identification

• Classification: Inorganic chemical industry >> Inorganic base
• Name: Dihydrogen hexahydroxyplatinate
• Synonyms: Hydrogenhexahydroxyplatinate (IV)
• Molecular Formula: H₈O₆Pt
• Molecular Weight: 299.14
• CAS Registry Number: 51850-20-5
• EC Number: 257-471-2
• SMILES: O[Pt-2](O)(O)(O)(O)O

Properties

• Water solubility: insoluble

Safety Data

• Hazard Symbols: GHS07 Warning
• Risk Statements: H315-H319-H332-H335
• Safety Statements: P261-P305+P351+P338

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Eye irritation	Eye Irrit.	2	H319
Acute hazardous to the aquatic environment	Aquatic Acute	1	H400
Chronic hazardous to the aquatic environment	Aquatic Chronic	1	H410
Acute toxicity	Acute Tox.	4	H332
Specific target organ toxicity - single exposure	STOT SE	3	H335
Skin irritation	Skin Irrit.	2	H315
Acute toxicity	Acute Tox.	4	H302
Respiratory sensitization	Resp. Sens.	1	H334
Skin sensitization	Skin Sens.	1	H317

Discovery and Applications

Dihydrogen hexahydroxyplatinate is a coordination compound involving platinum in a complex anionic form, often represented by the formula H₂[Pt(OH)₆]. This compound is related to platinum hexahydroxyplatinate complexes, where platinum is coordinated by six hydroxide (OH⁻) ligands, forming an octahedral geometry around the central platinum ion.

The compound typically exists in aqueous solution and can be considered as a hydrated platinum complex ion with platinum in the +4 oxidation state. It is part of the family of platinum hydroxide complexes, which are intermediates or species formed during the chemical transformation of platinum salts in alkaline media.

Historically, hexahydroxyplatinate complexes have been studied as part of the chemistry of platinum in alkaline solutions, including the formation and behavior of soluble platinum complexes in hydrothermal processes, catalysis, and electrochemical systems. These species are relevant in understanding platinum's speciation and reactivity under basic conditions.

In terms of preparation, hexahydroxyplatinate ions are often generated by treating platinum(IV) salts, such as hexachloroplatinate(IV), with concentrated alkali solutions, leading to ligand exchange where chloride ligands are replaced by hydroxide ions. The resulting aqueous solution contains the hexahydroxyplatinate anion, which may be isolated or studied in situ.

The coordination environment of platinum in the hexahydroxyplatinate ion is octahedral, with six hydroxide ligands symmetrically arranged around the metal center. This geometry is common for d⁶ metal ions in the +4 oxidation state and contributes to the stability of the complex in solution.

Applications of platinum hydroxide complexes such as dihydrogen hexahydroxyplatinate are primarily found in catalysis, where platinum species act as active sites or precursors to supported platinum catalysts used in hydrogenation, oxidation, and other important industrial reactions. Understanding these hydroxide complexes aids in catalyst preparation and regeneration processes.

Analytically, these complexes can be characterized by techniques such as ultraviolet-visible (UV-Vis) spectroscopy, which shows characteristic ligand-to-metal charge transfer bands, and infrared (IR) spectroscopy, which identifies hydroxide ligand vibrations. Nuclear magnetic resonance (NMR) spectroscopy is less common due to the paramagnetic nature of many platinum complexes, but mass spectrometry and X-ray absorption spectroscopy (XAS) are also utilized to study their structure and oxidation states.

Dihydrogen hexahydroxyplatinate is generally stable under alkaline conditions but may decompose or transform upon acidification, leading to the formation of other platinum species, such as hexachloroplatinate or platinum hydroxide precipitates.

In summary, dihydrogen hexahydroxyplatinate is a platinum(IV) complex featuring six hydroxide ligands coordinated octahedrally to the metal center. It is mainly relevant in platinum chemistry under alkaline conditions and plays a role in catalysis and the understanding of platinum speciation in solution.

References

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