Sodium hexachloropalladate (IV)
[CAS# 53823-60-2]

Identification

• Classification: Inorganic chemical industry >> Inorganic salt >> Metal halides and halides >> Metal chlorides and salts
• Name: Sodium hexachloropalladate (IV)
• Synonyms: Disodium hexachloropalladium(2-)
• Molecular Formula: Cl₆Na₂Pd
• Molecular Weight: 365.12
• CAS Registry Number: 53823-60-2
• SMILES: [Na+].[Na+].Cl[Pd-2](Cl)(Cl)(Cl)(Cl)Cl

Safety Data

• Hazard Symbols: GHS07 Warning
• Hazard Statements: H315-H319-H335
• Precautionary Statements: P261-P264-P271-P280-P302+P352-P304+P340-P305+P351+P338-P312-P362-P403+P233-P501

Discovory and Applicatios

Sodium hexachloropalladate(IV), with the chemical formula Na₂\[PdCl₆], is an inorganic coordination compound consisting of a palladium(IV) center surrounded by six chloride ligands in an octahedral geometry. The complex is stabilized by two sodium cations that balance the -2 charge of the hexachloropalladate anion. It appears as a reddish-brown crystalline solid that is soluble in water and stable under normal laboratory conditions.

The compound is typically prepared by the oxidation of palladium(II) salts, such as palladium(II) chloride (PdCl₂), in the presence of hydrochloric acid and a strong oxidizing agent like chlorine gas or nitric acid. The high oxidation state of palladium in this complex (+4) is less common than the +2 state, making this compound of special interest in both coordination chemistry and catalytic research.

Sodium hexachloropalladate(IV) is used primarily as a precursor in the synthesis of other palladium compounds and as a reagent in inorganic and organometallic chemistry. It has been employed in studies on redox behavior of palladium complexes and as a starting material for the preparation of heterogeneous or supported palladium catalysts. Due to the reactivity of the Pd(IV) center, it can undergo reductive elimination reactions, making it a valuable intermediate for certain types of ligand substitution and electron-transfer processes.

In analytical chemistry, hexachloropalladate complexes have been studied for their spectrophotometric properties. The complex exhibits characteristic absorption in the visible region, which allows for its detection and quantification in solution. The spectral features can be influenced by ligand exchange, solvation, and redox transformations, making the compound useful in examining the behavior of palladium in complex systems.

The structure of \[PdCl₆]²⁻ is octahedral, with all six chloride ions coordinated symmetrically around the palladium center. This geometry and the d⁶ electron configuration of Pd(IV) contribute to the compound’s stability in acidic and moderately oxidizing aqueous media. However, it can be reduced to palladium(II) or elemental palladium under appropriate conditions, a property that underlies many of its catalytic applications.

In catalysis, palladium(IV) species are often invoked as intermediates in oxidation reactions and cross-coupling processes. While Pd(II) is more commonly used in practice, Pd(IV) complexes such as sodium hexachloropalladate(IV) have been studied for their ability to facilitate oxidative addition steps and promote carbon–heteroatom bond formation. Research into Pd(IV) chemistry continues to explore its potential in green chemistry and high-valent transition-metal catalysis.

Sodium hexachloropalladate(IV) must be handled with care, as palladium compounds can be toxic and irritant upon exposure. Standard laboratory safety practices such as use of gloves, eye protection, and fume hoods are recommended. The compound should be stored in tightly sealed containers to prevent hydrolysis or decomposition, especially in the presence of light or reducing agents.

In summary, sodium hexachloropalladate(IV) is a coordination compound of palladium in the +4 oxidation state, used in synthetic, catalytic, and analytical chemistry. Its stability, redox properties, and ability to participate in ligand exchange make it a useful tool in the development of palladium-based chemical processes.