Rhodium (III) sulfide – an inorganic compound

Rhodium (III) sulfide is the inorganic compound with the formula Rh2S3. It is a moderately water and acid soluble Rhodium source for uses compatible with sulfates. It is an insoluble black solid, prepared by heating a mixture of elemental rhodium and sulfur. It is a red crystal that forms a hydrated solution at high temperatures.

Rhodium (III) sulfide is an anhydrous metal sulfate that is formed by oxidizing rhodium with concentrated sulphuric acid.

General Information

  • Molecular Formula: Rh2S3
  • Average mass: 302.006 Da
  • Monoisotopic mass: 301.727203 Da

Sulfate compounds are salts or esters of sulfuric acid formed by replacing one or both of the hydrogens with a metal. Crystals can be grown by chemical vapor transport using bromine as the transporting agent. Most metal sulfate compounds are readily soluble in water for uses such as water treatment, unlike fluorides and oxides which tend to be insoluble. The metal sulfides are synthesized on carbon by reacting metal chlorides with hydrogen sulfide at 350°C. Mixtures of Cu, Co, Fe, and Ni salts with RhCl3 formed thiospinels.

The structure consists of octahedral and tetrahedral Rh and S centers, respectively. No close Rh-Rh contacts are observed. Rh2Se3 and Ir2S3 adopt the same structure as Rh2S3. This product is not compatible with bases, halides, water, cyclopentadiene, cyclopentanone, oxime, nitroaryl amines, haxalithium disilicide, phosphorus (III) oxide, chlorine bromine pentafluoride, trifluoride, and oxygen difluoride (OF2). Rhodium plated electrodes are used in the soda industry for electrolysis of salt water, and for electrodes for domestic water treatment.

Rhodium (III) sulfide is majorly used in the production of high performance coatings by electroplating technique. It is used as plating reagents and additives for noble metal. It is also used for fancy plating rhodium in jewellery and horologe. The main uses of rhodium are catalytic. Rhodium plating is used widely in the jewelry industry. In the electronics industry, rhodium plating is used for electrical contacts in, e.g., ferreed switches.