Pyromellitic acid–sarcosine (1/2)

The title compound, C(10)H(6)O(8)·2C(3)H(7)NO(2), crystallizes as an adduct with the acid and amino acid mol­ecules in their neutral forms. The asymmetric unit contains one half of a centrosymmetric pyromellitic acid mol­ecule and one sarcosine mol­ecule. The sarcosine has the amine group protonated and the carboxyl group deprotonated, as is usual for amino acids (zwitterionic form). The pyromellitic acid mol­ecules retain the four carboxyl H atoms with the carboxyl groups rotated out of the ring plane [O—C—C—C torsion angles = 24.1 (3) and 61.6 (2)°]. There is a three-dimensional hydrogen-bond network linking the mol­ecules.