4,5-Dimethoxy­cyclo­pent-4-ene-1,2,3-trione.

The title compound (alternative name dimethyl croconate), C7H6O5, is the first example of a croconate ether. The mol­ecule is essentially planar and exhibits a local symmetry ( C2 v) that is different from that shown by the croconate dianion ( C5 h), indicating that the geometry of these compounds is very sensitive to the electric charge state. [ABSTRACT FROM AUTHOR]