Platinum nitrate
[CAS# 18496-40-7]

Identification

• Classification: Inorganic chemical industry >> Inorganic salt >> Metal nitrates and nitrites
• Name: Platinum nitrate
• Synonyms: Platinum(II) nitrate; Platinum dinitrate
• Molecular Formula: Pt(NO₃)₂
• Molecular Weight: 319.09
• CAS Registry Number: 18496-40-7
• EC Number: 242-383-9
• SMILES: [N+](=O)([O-])[O-].[N+](=O)([O-])[O-].[Pt+2]

Safety Data

• Hazard Symbols: GHS03;GHS05;GHS06;GHS07;GHS09 Danger
• Risk Statements: H271-H290-H301-H314-H317-H318-H400-H410
• Safety Statements: P210-P220-P234-P260-P261-P264-P264+P265-P270-P272-P273-P280-P283-P301+P316-P301+P330+P331-P302+P352-P302+P361+P354-P304+P340-P305+P354+P338-P306+P360-P316-P317-P321-P330-P333+P317-P362+P364-P363-P370+P378-P371+P380+P375-P390-P391-P405-P406-P420-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Serious eye damage	Eye Dam.	1	H318
Substances or mixtures corrosive to metals	Met. Corr.	1	H290
Skin corrosion	Skin Corr.	1A	H314
Acute hazardous to the aquatic environment	Aquatic Acute	1	H400
Chronic hazardous to the aquatic environment	Aquatic Chronic	1	H410
Oxidising solids	Ox. Sol.	1	H271
Oxidising solids	Ox. Sol.	2	H271
Oxidising solids	Ox. Sol.	2	H272
Skin sensitization	Skin Sens.	1	H317
Respiratory sensitization	Resp. Sens.	1	H334
Acute toxicity	Acute Tox.	4	H302
Skin irritation	Skin Irrit.	2	H315
Skin corrosion	Skin Corr.	1B	H314
Eye irritation	Eye Irrit.	2	H319
Acute toxicity	Acute Tox.	4	H332

Discovery and Applications

Platinum nitrate, typically represented by the chemical formula Pt(NO₃)₂, is an inorganic compound consisting of platinum in the +2 oxidation state coordinated to nitrate ions. It appears as a crystalline solid and is soluble in water and certain polar solvents. While pure platinum nitrate is less commonly encountered in bulk form compared to other platinum salts, it serves as a valuable precursor in platinum chemistry and catalysis.

The compound is generally prepared by the reaction of platinum metal or platinum salts with concentrated nitric acid. This process oxidizes platinum to its +2 oxidation state and coordinates nitrate ligands, forming platinum nitrate complexes. The exact stoichiometry and structure of platinum nitrate may vary, with reported species including hydrated forms and complex nitrato ligands.

Structurally, platinum nitrate features a square planar coordination geometry around the platinum(II) center, a common arrangement for d⁸ transition metal ions. The nitrate ligands coordinate through oxygen atoms, acting as monodentate or potentially bridging ligands depending on the complex form. This coordination affects the compound’s solubility, reactivity, and thermal stability.

Platinum nitrate is utilized primarily as a precursor for the synthesis of other platinum compounds and catalysts. In particular, it serves as a source of platinum in the preparation of supported platinum catalysts widely used in heterogeneous catalysis for hydrogenation, oxidation, and reforming reactions in chemical industry. The nitrate ligands can be decomposed thermally, leaving behind metallic platinum dispersed on supports such as alumina or carbon.

In material science, platinum nitrate finds applications in the fabrication of platinum thin films and nanoparticles through processes like chemical vapor deposition or solution-based synthesis. Its ability to release platinum under controlled conditions makes it a useful reagent in these advanced manufacturing techniques, contributing to electronics, fuel cells, and catalytic converter technologies.

From an analytical perspective, platinum nitrate solutions are employed in certain chemical analyses involving platinum determination or as reference materials in catalytic studies. Its well-defined chemistry allows for controlled experiments exploring platinum’s redox and coordination behaviors.

Handling of platinum nitrate requires care due to its oxidizing nature and potential health hazards associated with platinum compounds. It is generally considered harmful if ingested or inhaled and may cause irritation upon contact with skin or eyes. Appropriate safety measures include use of personal protective equipment, working in ventilated areas, and proper storage away from reducing agents and organic materials.

Thermally, platinum nitrate decomposes upon heating, releasing nitrogen oxides and leaving platinum oxide or metallic platinum residues. This behavior is exploited in catalyst preparation but necessitates controlled conditions to avoid uncontrolled release of toxic gases.

In summary, platinum nitrate is a platinum(II) nitrate complex serving as an important precursor in platinum chemistry. Its roles include catalyst synthesis, materials fabrication, and analytical applications. The compound’s structural features and chemical behavior make it valuable in industrial and research contexts, particularly in processes requiring controlled platinum delivery and deposition.

References

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