Chromium(III) sulfide

Chromium(III) sulfide is an inorganic compound with the chemical formula Cr₂S₃. It is one of the sulfides of chromium, where chromium is in the +3 oxidation state. This compound is known for its black color and is typically found as a powder.

Structure and Properties

Chromium(III) sulfide is composed of chromium cations (Cr³⁺) and sulfide anions (S²⁻). The compound crystallizes in a structure similar to that of aluminum oxide, with chromium ions occupying octahedral sites.

The compound is insoluble in water, which is a common characteristic of many metal sulfides. It has a high melting point of approximately 1350 °C, indicating strong ionic bonds between the chromium and sulfide ions.

Synthesis

Chromium(III) sulfide can be synthesized through the direct combination of elemental chromium and sulfur at high temperatures:

<math>2 Cr + 3 S \rightarrow Cr_2S_3</math>

Alternatively, it can be prepared by the reaction of chromium(III) chloride with hydrogen sulfide:

<math>2 CrCl_3 + 3 H_2S \rightarrow Cr_2S_3 + 6 HCl</math>

Applications

While not as widely used as other chromium compounds, chromium(III) sulfide has potential applications in materials science, particularly in the development of advanced ceramics and as a pigment due to its stable black color.

Safety and Handling

Chromium(III) sulfide should be handled with care, as with all chemical compounds. Although it is less toxic than chromium(VI) compounds, it is advisable to avoid inhalation or ingestion. Proper personal protective equipment, such as gloves and goggles, should be used when handling this compound.

Also see

• Chromium(III) oxide
• Chromium(III) chloride
• Sulfide minerals
• Transition metal sulfides