Dichromatebased

Dichromatebased describes substances or systems that incorporate the dichromate anion Cr2O7^2−, typically paired with potassium, sodium, or ammonium counterions. In aqueous solution dichromate is interconvertible with chromate CrO4^2−; the balance shifts with pH, giving characteristic orange-red coloration under acidic conditions and yellow-green for chromate under basic conditions.

Common forms include potassium dichromate K2Cr2O7, sodium dichromate Na2Cr2O7, and ammonium dichromate (NH4)2Cr2O7. They are strong oxidizing agents, particularly in acidic media, capable of oxidizing primary and secondary alcohols and various organic substrates. They are also used in some qualitative analyses and in photoresists.

In photography and microfabrication, dichromate-based reagents are used in light-sensitive gelatin and polymer resists; exposure to UV light crosslinks the material via Cr(VI)-mediated oxidation, enabling pattern development by washing away unexposed areas. Historically, dichromate reagents were used as oxidants in organic synthesis and as qualitative oxidizing reagents in analytical chemistry.

Safety and environmental considerations: Cr(VI) species are toxic and carcinogenic; exposure limits exist; disposal requires reduction to Cr(III) before disposal; many jurisdictions regulate use. Proper handling, containment, and adherence to regulatory guidelines are essential when working with dichromate-based materials.