What is "dichromic acid"

n. (context inorganic compound English) A relatively unstable form of chromic acid, H₂Cr₂O₇, known only in solution or as its salts, the dichromates, from which it may be prepared.

n. the hypothetical acid (H2Cr2O7) from which dichromates are derived; known only in solution and in the form of dichromate salts