Platinum(ii) chloride (Cl2Pt) is 73.3% platinum by mass, a dark brown powder that suppliers make almost entirely from chloroplatinic acid rather than isolating it directly from ore. One CAS registry number, 10025-65-7, and one PubChem identity, CID 2770, fix its formula, molecular weight and hazard data across every catalog that lists it. What does its solid-state structure look like, why does it feed into higher-value platinum complexes and catalysts, and what does a real order of it cost to place? Its identity, bonding, platinum content, physical properties, preparation, uses, commercial grades and hazard classification follow section by section.
What Is Platinum(ii) chloride?#
Platinum(ii) chloride is a binary platinum(II) halide, the platinum group metal named directly in its own formula, Cl2Pt. PubChem catalogs the compound under CID 2770, gives its systematic name as "dichloroplatinum," and lists CAS number 10025-65-7 as the sole registered identifier, a number Sigma-Aldrich, TCI America and the European Chemicals Agency all use for the same substance. Older literature also carries the compound as platinum dichloride, platinous chloride and, in 19th-century usage, muriate of platinum. Platinum(ii) chloride is one of the platinum group metal compounds and catalysts cataloged with a dedicated CAS registry entry on this site.
| Property | Value |
|---|---|
| Preferred name | Platinum(II) chloride |
| Alternate names | platinum dichloride; platinous chloride; muriate of platinum |
| CAS number | 10025-65-7 |
| PubChem CID | 2770 |
| PubChem IUPAC name | dichloroplatinum |
| InChIKey | CLSUSRZJUQMOHH-UHFFFAOYSA-L |
| Molecular formula | Cl2Pt |
| Molecular weight | 265.99 g/mol |
| Platinum group metal | platinum (Pt), element 78 |
Platinum(ii) chloride Structure and Bonding#
Platinum(ii) chloride's common form, called beta-PtCl2, is a hexameric Pt6Cl12 cluster, not a simple two-atom molecule despite its Cl2Pt formula. Six square-planar PtCl4 units link into a hexagonal cell of a = 13.126 angstrom and c = 8.666 angstrom, per a 2003 crystal-structure paper by von Schnering and coauthors in Zeitschrift für anorganische und allgemeine Chemie. The platinum-chlorine bond length is 2.315 angstrom, and adjacent platinum atoms sit 3.339 angstrom apart, a short contact the same study found does not amount to a true platinum-platinum bond. Each platinum center carries the d8 configuration typical of square-planar platinum(II) chemistry.
Heating the beta cluster to 500°C converts it into alpha-PtCl2, a polymeric, disordered structure of the same square-planar PtCl4 units joined edge to edge and corner to corner instead of into discrete clusters, per Wikipedia's platinum(II) chloride entry.
PGM Content of Platinum(ii) chloride#
Platinum(ii) chloride is 73.3 wt% platinum, computed from platinum's atomic mass of 195.08 g/mol divided by the compound's own molecular weight of 265.99 g/mol (195.08 / 265.99 = 0.733). No supplier assay figure for this ratio is published separately; the value follows directly from the compound's fixed formula, Cl2Pt, so every batch sold at stated purity carries the same contained-platinum fraction regardless of pack size. That fixed ratio is why buyers and refiners price PtCl2 against contained platinum value rather than a flat per-gram catalog number, tracked day to day on DailyPlatinum's platinum price today page.
Physical and Chemical Properties#
Platinum(ii) chloride is a dark brown, diamagnetic, odorless powder that is insoluble in water but dissolves in hydrochloric acid and in ammonia, according to Wikipedia's platinum(II) chloride entry. It melts at 581°C and has a density of 6.05 g/cm3. On strong heating, separately from the 500°C alpha-beta phase change above, the solid also decomposes to release hydrogen chloride and other corrosive gases, per ChemicalBook's material safety data sheet.
| Property | Value | Basis |
|---|---|---|
| Appearance | Dark brown, diamagnetic, odorless powder | Wikipedia |
| Solubility | Insoluble in water; soluble in hydrochloric acid and ammonia | Wikipedia |
| Melting point | 581°C | Wikipedia |
| Density | 6.05 g/cm3 | Wikipedia |
| Alpha-beta phase transition | 500°C (hexameric beta to polymeric alpha) | Wikipedia |
| Thermal decomposition | Releases hydrogen chloride and other corrosive gases on strong heating | ChemicalBook (single-source) |
| Molecular weight | 265.99 g/mol | PubChem CID 2770 |
How Is Platinum(ii) chloride Made?#
Chloroplatinic acid is the starting material for the principal industrial route to platinum(ii) chloride, heated to 350°C in air. The reaction, H2PtCl6 to PtCl2 + Cl2 + 2 HCl, is the preferred method because chloroplatinic acid is itself made directly from platinum metal, according to Wikipedia's platinum(II) chloride entry. Two further routes cover the same conversion:
- Reduce aqueous chloroplatinic acid with hydrazinium salts, a more labor-intensive alternative to thermal decomposition.
- Over-chlorinate platinum metal to platinum(IV) chloride first, then thermally strip it back to platinum(ii) chloride at 450°C (PtCl4 to PtCl2 + Cl2), a reaction sequence also used as a gravimetric assay for platinum purity, since further heating drives off the remaining chlorine and leaves metallic platinum behind.
What Is Platinum(ii) chloride Used For?#
Platinum(ii) chloride is used as a precursor to platinum(II) coordination complexes and platinum-based pharmaceuticals, rather than as a finished product in its own right. It supplies platinum to further syntheses by way of the intermediate potassium tetrachloroplatinate (K2PtCl4), per Wikipedia's platinum(II) chloride entry, and any resulting platinum drug is named here only as a downstream use, with dosing and clinical detail left to the border section below.
Precursor Role#
Potassium tetrachloroplatinate, made from platinum(ii) chloride, is itself the branch point for three named platinum complexes: Zeise's salt, Magnus's green salt and PtCl2(PPh3)2-type phosphine complexes. K2PtCl4 combines with ethylene to give Zeise's salt and with tetraamineplatinum(II) chloride to give Magnus's green salt, standard preparations documented in the compound's own Wikipedia entry.
Platinum(ii) chloride also feeds industrial silicone catalysis directly, as the traditional starting material for Karstedt's catalyst, reacted with divinyltetramethyldisiloxane (DVTMS) in methyl ethyl ketone (MEK). That traditional route converts only 80 to 85% of the PtCl2 over 8 to 10 hours, with the catalyst thermally decomposing on extended runs. A 2023 study in ACS Catalysis found that presoaking PtCl2 in MEK first forms a crystalline intermediate, Pt6Cl12·(MEK)1.5, raising conversion to 99% in just 4 hours.
Commercial Forms, Purity and Price#
Platinum(ii) chloride is sold as a laboratory powder at three trace-metals purity grades, 98%, 99.9% and 99.99%, alongside a nominal "73% Pt for synthesis" grade, according to Sigma-Aldrich's product catalog. TCI America lists its P1920 product above 95.0% purity, and Thermo Scientific/Alfa Aesar sell a 98% grade in 1 gram packs. American Elements additionally supplies the compound in bulk formats, up to palletized 5-gallon or 25 kilogram pails and 1-ton super sacks, extending the same identity well beyond milligram research packs.
| Grade | Purity | Pack size class | Form |
|---|---|---|---|
| Research grade | 98% | Milligram to multi-gram (TCI, Thermo Scientific, Alfa Aesar) | Dark brown powder |
| High-purity grade | 99.9% trace-metals-basis, 73% Pt min | Gram-scale (Alfa) | Dark brown powder |
| Ultra-high-purity grade | 99.99% trace-metals-basis | Gram-scale (Sigma-Aldrich) | Dark brown powder |
| Bulk / industrial grade | Supplier-stated commercial purity | 5-gallon pails up to 1-ton super sacks (American Elements) | Dark brown powder |
Safety and Hazard Classification#
Danger is the GHS signal word on file for platinum(ii) chloride. GHS classification reported to PubChem: Danger; H290, H314, H315, H317, H319, H334, H413. Across the 75 company reports the European Chemicals Agency's C&L Inventory aggregates for the compound (mirrored on PubChem), 92% flag H317 (may cause an allergic skin reaction) and H334 (may cause allergy, asthma or breathing difficulties if inhaled) as the two most consistently reported codes, ahead of H314, severe skin burns and eye damage, at 61.3%.
Platinum(ii) chloride falls under the "platinum, soluble salts" exposure category, for which both OSHA's permissible exposure limit and the ACGIH threshold limit value are set at 0.002 mg/m3, as platinum. HSDB's occupational-hazard summary, mirrored on PubChem, reports that inhalation-related allergy, including bronchial asthma, rhinitis and conjunctivitis, is common in the platinum industry and traces to sensitization against platinum chloride salts specifically, with HSDB citing an average of 60% of platinum-industry workers historically affected by bronchial asthma. For transport, ChemicalBook's safety data sheet assigns platinum(ii) chloride UN number 3260, a corrosive solid, hazard class 8, and the same data sheet recommends storing it in a tightly closed container in a cool, dry, well-ventilated area away from oxidizers. The compound is also listed on Australia's Inventory of Industrial Chemicals and New Zealand's EPA Inventory of Chemical Status.
Where Platinum(ii) chloride Chemistry Stops: Medical and Pharmaceutical Platinum#
This page covers platinum(ii) chloride as an industrial precursor and reagent only, not as a treatment. The platinum pharmaceuticals it eventually feeds into, by way of the intermediates and complexes named above, carry their own dosing, regimen and side-effect profiles that belong to medicine, not to a compound's chemistry page. Readers looking for that clinical content, or for a fuller view of platinum's compound chemistry, can continue to DailyPlatinum's platinum compounds page or the site's medical-applications coverage.
Related PGM Compounds#
Platinum(ii) chloride sits at the center of a short chain of named platinum salts and complexes built from it or closely related to it by oxidation state.
| Compound | Formula / composition | Relationship to platinum(ii) chloride |
|---|---|---|
| Platinum(IV) chloride | PtCl4 | The Pt(IV) counterpart; one of the three named routes to platinum(ii) chloride thermally strips one chlorine equivalent from it (PtCl4 to PtCl2 + Cl2) |
| Chloroplatinic acid | H2PtCl6 | The principal starting material used to make platinum(ii) chloride by thermal decomposition |
| Potassium tetrachloroplatinate | K2PtCl4 | The direct downstream salt made from platinum(ii) chloride, and the branch point for Zeise's salt and Magnus's green salt |
| Karstedt's catalyst | Pt2(DVTMS)3 complex | A commercial silicone hydrosilylation catalyst made from platinum(ii) chloride and DVTMS |
History#
Platinum(ii) chloride still carries platinous chloride and, in 19th-century usage, muriate of platinum among its recorded synonyms, preserved in PubChem's identifier list for CID 2770. The "-ous" suffix reflects the older naming system chemists used for a metal's lower oxidation state, before Stock nomenclature introduced the Roman-numeral platinum(II) used throughout this page. Its own hexameric solid-state structure, described above, was not resolved by X-ray crystallography until 2003, well after the compound had long been in synthetic use.
Frequently Asked Questions#
What is the name for PtCl4? PtCl4 is platinum(IV) chloride, CAS 13454-96-1, the platinum(IV) counterpart to platinum(ii) chloride and a distinct compound with its own molecular weight of 336.9 g/mol.
What is the chemical name for PdCl2? PdCl2 is palladium(II) chloride, CAS 7647-10-1, a chloride of the sibling platinum group metal palladium rather than of platinum.
What chloride is insoluble in water? Platinum(ii) chloride itself is insoluble in water; it dissolves instead in hydrochloric acid and in ammonia, per Wikipedia's platinum(II) chloride entry.