Ammonium hexachloroplatinate

Chemical compound

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Ammonium hexachloroplatinate, also known as ammonium chloroplatinate, is a chemical compound with the formula (NH₄)₂[PtCl₆]. It is a yellow solid that is sparingly soluble in water. This compound is an important platinum salt and is used in various applications, including the purification of platinum and in analytical chemistry.

Structure and Properties

Ammonium hexachloroplatinate is composed of the ammonium cation (NH₄⁺) and the hexachloroplatinate anion ([PtCl₆]^2_). The platinum atom is in the +4 oxidation state and is coordinated by six chloride ions in an octahedral geometry. This coordination complex is typical for platinum(IV) compounds.

The compound is a yellow crystalline solid. It is only slightly soluble in water, which makes it useful for the precipitation of platinum from solutions. The low solubility is a result of the strong ionic interactions within the crystal lattice.

Preparation

Ammonium hexachloroplatinate is typically prepared by the reaction of platinum(IV) chloride with ammonium chloride in aqueous solution. The reaction can be represented as follows:

<math>\text{PtCl}_4 + 2 \text{NH}_4\text{Cl} \rightarrow (\text{NH}_4)_2[\text{PtCl}_6]</math>

The product precipitates out of the solution as a yellow solid due to its low solubility.

Applications

Ammonium hexachloroplatinate is primarily used in the purification of platinum. It is a key intermediate in the separation of platinum from other metals. The compound is also used in analytical chemistry for the quantitative determination of platinum.

In the laboratory, ammonium hexachloroplatinate can be used to prepare other platinum compounds. For example, it can be reduced to produce platinum black, a finely divided form of platinum used as a catalyst.

Safety and Handling

As with many platinum compounds, ammonium hexachloroplatinate should be handled with care. It can cause skin and respiratory irritation. Proper protective equipment, such as gloves and goggles, should be used when handling the compound.

Related pages

• Platinum
• Coordination complex
• Analytical chemistry