Sodium dichromate dihydrate

Sodium dichromate dihydrate (CAS 7789-12-0), also known as disodium dichromate dihydrate, is an inorganic chromium(VI) salt supplied as a crystalline solid. It is one of the most commercially significant chromate compounds in industrial chemistry, serving as a primary source of hexavalent chromium in manufacturing processes.

In leather tanning, sodium dichromate dihydrate acts as an oxidising precursor that converts to trivalent chromium in the presence of reducing agents, enabling chrome tanning of hides. It also functions as a corrosion inhibitor in metal surface treatment, forming a protective oxide layer on aluminium and zinc substrates, and serves as a catalyst or oxidant in textile dyeing to fix certain dye classes onto fibres.

This compound is subject to REACH authorisation requirements under Annex XIV due to its classification as a substance of very high concern (SVHC). Procurement requires confirmed authorisation or exemption documentation. It is typically available in technical grade and supplied in sealed drums or bulk quantities depending on volume requirements.