Platinum dichloride
[CAS# 10025-65-7]

Identification

• Classification: Inorganic chemical industry >> Inorganic salt >> Metal halides and halides >> Metal chlorides and salts
• Name: Platinum dichloride
• Synonyms: Platinum(II) chloride
• Molecular Formula: PtCl₂
• Molecular Weight: 265.99
• CAS Registry Number: 10025-65-7
• EC Number: 233-034-1
• SMILES: Cl[Pt]Cl

Properties

• Density: 6.05 g/mL (Expl.)
• Melting point: 581 ºC (Decomposes) (Expl.)
• Solubility: Insoluble (water, alcohol, ether). soluble (HCl, NH4OH) (Expl.)

Safety Data

• Hazard Symbols: GHS05;GHS07;GHS08 DangerGHS05
• Hazard Statements: H290-H314-H315-H317-H319-H334-H413
• Precautionary Statements: P233-P234-P260-P261-P264-P264+P265-P271-P272-P273-P280-P284-P301+P330+P331-P302+P352-P302+P361+P354-P304+P340-P305+P351+P338-P305+P354+P338-P316-P321-P332+P317-P333+P317-P337+P317-P342+P316-P362+P364-P363-P390-P403-P405-P406-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Skin sensitization	Skin Sens.	1	H317
Respiratory sensitization	Resp. Sens.	1	H334
Skin corrosion	Skin Corr.	1B	H314
Skin irritation	Skin Irrit.	2	H315
Substances or mixtures corrosive to metals	Met. Corr.	1	H290
Eye irritation	Eye Irrit.	2	H319
Chronic hazardous to the aquatic environment	Aquatic Chronic	4	H413
Serious eye damage	Eye Dam.	1	H318

• Transport Information: UN 3260

Discovory and Applicatios

Platinum dichloride, commonly referred to as platinum(II) chloride, is an inorganic compound with the chemical formula PtCl₂. It is composed of platinum in the +2 oxidation state coordinated to two chloride ions. This compound exists in several forms, including a polymeric brown solid and a green crystalline form, depending on the preparation method and the degree of hydration. It is one of the key starting materials in platinum coordination chemistry and has significant relevance in both academic and industrial settings.

The discovery and study of platinum dichloride can be traced back to early investigations into the chemistry of platinum in the 19th century, during which various chloroplatinate salts and simple platinum halides were first synthesized and characterized. Systematic studies of platinum(II) chloride and its reactivity laid the foundation for the development of coordination chemistry and the understanding of square planar complexes, which are characteristic of platinum(II) compounds.

Platinum dichloride is typically prepared by reducing platinum(IV) chloride (PtCl₄) or chloroplatinic acid (H₂PtCl₆) under controlled conditions. Heating chloroplatinic acid with hydrogen gas or by thermal decomposition results in the formation of platinum(II) chloride. It is often obtained as a brownish or dark green solid, which is poorly soluble in water but reacts with hydrochloric acid and other ligands.

In coordination chemistry, PtCl₂ is a useful precursor for synthesizing a wide range of platinum(II) complexes. It readily reacts with ligands such as phosphines, amines, and olefins to form square planar complexes of the type \[PtCl₂L₂], where L is a neutral ligand. These complexes have been extensively studied for their structural and electronic properties and play a role in catalysis, materials science, and bioinorganic chemistry.

One of the most notable applications of platinum dichloride is in the synthesis of cisplatin (cis-diamminedichloroplatinum(II)), a landmark anticancer drug discovered in the 1960s. Cisplatin is synthesized by reacting PtCl₂ with ammonia under specific conditions that favor the formation of the cis isomer. The success of cisplatin in chemotherapy prompted extensive research into platinum-based drugs and derivatives, many of which originate from platinum dichloride as a key starting material.

Beyond pharmaceuticals, platinum dichloride has applications in catalysis. It is used in homogeneous and heterogeneous catalytic systems for hydrogenation, hydrosilylation, and other organometallic transformations. Platinum(II) catalysts derived from PtCl₂ are valued for their ability to activate small molecules and mediate bond-forming reactions with high selectivity.

In analytical and materials chemistry, PtCl₂ is employed in the preparation of platinum-containing thin films, nanoparticles, and ceramics. These materials are of interest for electronic, optical, and catalytic applications. The compound also finds use in platinum plating and electrochemical studies.

The structure of platinum dichloride depends on its physical form. In the polymeric form, each platinum atom is coordinated by four chloride ligands in a distorted square planar geometry, with bridging chlorides linking adjacent platinum centers. This leads to a one-dimensional chain structure. In solution, the compound may dissociate into monomeric or dimeric species, depending on the solvent and ligand environment.

Handling of platinum dichloride requires caution, as it is a heavy metal compound and may pose health risks upon inhalation or ingestion. Appropriate safety measures include the use of gloves, protective clothing, and ventilation when working with the solid or its solutions.

In summary, platinum dichloride is a fundamental platinum(II) compound with broad utility in coordination chemistry, catalysis, pharmaceuticals, and materials science. Its ability to form stable complexes with a wide variety of ligands makes it a versatile intermediate in both academic research and industrial applications.

References

2008. Comparison of the electronic properties, and thermodynamic and kinetic parameters of the aquation of selected platinum(II) derivatives with their anticancer IC50 indexes. Journal of Molecular Modeling, 14(3).
DOI: 10.1007/s00894-008-0285-0

2017. Direct measurement of interaction forces between a platinum dichloride complex and DNA molecules. Journal of Biological Physics, 43(3).
DOI: 10.1007/s10867-017-9456-5

2010. Histopathological alterations and induction of hsp70 in ramshorn snail (Marisa cornuarietis) and zebrafish (Danio rerio) embryos after exposure to PtCl(2). Aquatic toxicology (Amsterdam, Netherlands), 99(2).
DOI: 10.1016/j.aquatox.2010.04.001