Overview
Platinum chloride is a collective term for inorganic compounds composed of platinum and chlorine. The most common species are platinum(II) chloride (PtCl₂) and platinum(IV) chloride (PtCl₄), which differ in the oxidation state of the metal and their structural characteristics.
Platinum(II) chloride (PtCl₂)
- Formula: PtCl₂
- Appearance: Dark‑brown powder; insoluble in water, soluble in concentrated hydrochloric acid and ammonia.
- Structure: Exists as both a monomeric PtCl₂ unit and polymeric forms such as hexameric [Pt₆Cl₁₂] clusters. The solid adopts a hexagonal crystal lattice.
- Physical properties: Molar mass 265.99 g·mol⁻¹; density ≈6.05 g·cm⁻³; melting point ≈581 °C (decomposes before boiling).
- Uses: Precursor for the synthesis of other platinum complexes, including anticancer agents (e.g., cisplatin) and catalysts for carbon‑carbon, carbon‑oxygen, and carbon‑nitrogen bond formation.
Platinum(IV) chloride (PtCl₄)
- Formula: PtCl₄
- Appearance: Brown solid; more soluble in water than PtCl₂, forming acidic solutions.
- Structure: Typically exists as a monomeric tetrahedral PtCl₄ unit or as ionic species [PtCl₆]²⁻ in solution.
- Physical properties: Molar mass 353.27 g·mol⁻¹; density ≈5.9 g·cm⁻³; decomposes on heating.
- Uses: Oxidizing agent and intermediate in the preparation of platinum(IV) complexes, which are investigated for catalytic and medicinal applications.
Chemical behavior
Both PtCl₂ and PtCl₄ are diamagnetic. PtCl₂ is a Lewis acid that can form adducts with ligands such as amines or phosphines. PtCl₄ can be reduced to PtCl₂ or metallic platinum under appropriate conditions.
Safety and hazards
- Classified as hazardous (GHS signal word “Danger”).
- Acute toxicity: LD₅₀ for oral exposure in rats ≈3423 mg·kg⁻¹ (PtCl₂).
- May cause skin and eye irritation; corrosive to metals. Proper personal protective equipment and engineering controls are required when handling.
References
- Wikipedia, “Platinum(II) chloride” – chemical formula, physical data, hazards.
- Wikipedia, “Platinum(IV) chloride” – structural information and applications.
Insufficient Encyclopedic Information: No additional distinct platinum‑chloride species beyond PtCl₂ and PtCl₄ are recognized in standard inorganic chemistry literature.
