Chloroplatinic acid

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Chloroplatinic acid is a chemical compound with the formula H₂PtCl₆·xH₂O, where x can vary but is often 6. This inorganic compound is a popular material in the field of chemistry, particularly in the synthesis of other platinum-based compounds and in the preparation of catalysts. It is a reddish-brown solid that dissolves in water to give bright yellow solutions, indicative of the presence of hexachloroplatinate(IV) anions.

Properties

Chloroplatinic acid is highly hygroscopic and deliquescent, meaning it can absorb moisture from the air and dissolve in it. When dissolved in water, it forms a hydrochloric acid solution and hexachloroplatinate, which is a key intermediate in many platinum-related chemical reactions. The compound is relatively stable, but it can be reduced to platinum metal by heating or by chemical reducers, making it a valuable source of platinum in both the laboratory and industry.

Synthesis

The synthesis of chloroplatinic acid typically involves the dissolution of platinum metal in aqua regia (a mixture of nitric acid and hydrochloric acid). The reaction produces chloroplatinic acid as well as nitrosyl chloride and other byproducts. The resulting solution can be evaporated to yield chloroplatinic acid crystals, which can be further purified by recrystallization.

Applications

Chloroplatinic acid has several important applications. In the field of material science, it is used to produce platinum-based catalysts, which are essential in various industrial processes, including the production of silicone and other organosilicon compounds. In analytical chemistry, chloroplatinic acid is employed in the determination of potassium by the gravimetric method, where potassium is precipitated as potassium hexachloroplatinate. Additionally, it serves as a precursor for the preparation of other platinum compounds used in cancer treatment and in nanotechnology for the synthesis of platinum nanoparticles.

Safety

Handling chloroplatinic acid requires caution. It is corrosive and can cause severe burns upon contact with skin or eyes. Additionally, its solutions emit hydrochloric acid fumes, which are harmful if inhaled. Proper safety equipment, such as gloves and eye protection, should always be used when working with this compound.

See also

• Platinum
• Aqua regia
• Catalyst
• Analytical chemistry