2-(Dicyanomethylene)croconate is a divalent anion with chemical formula or ((N≡C−)2C=)(C5O4)2−. It is one of the pseudo-oxocarbon anions, as it can be described as a derivative of the croconate oxocarbon anion through the replacement of one oxygen atom by a dicyanomethylene group =C(−C≡N)2.
The anion was synthesized and characterized by A. Fatiadi in 1980, by hydrolysis of croconate violet treated with potassium hydroxide.Alexander J. Fatiadi (1980), "Pseudooxocarbons. Synthesis of 1,2,3-tris(dicyanomethylene)croconate salts. A new bond-delocalized dianion, croconate blue". Journal of Organic Chemistry volume 45, pages 1338–1339. It gives an orange solution in water.
See also Croconate violet, 1,3-bis(dicyanomethylene)croconate Croconate blue, 1,2,3-tris(dicyanomethylene)croconate 1,2-Bis(dicyanomethylene)squarate 1,3-Bis(dicyanomethylene)squarate
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