title: Tetra-methyl biphenyl-2,3,3',4'-tetra-carboxyl-ate.
abstract: The asymmetric unit of the title compound, C(20)H(18)O(8), contains two mol-ecules with small geometric differences. The dihedral angles between the benzene rings are 62.94 (12) and 59.99 (12)°. The dihedral angles between the carboxylate groups in the 2- and 3-positions are 81.72 (13) and 65.54 (15)°, respectively. However, the dihedral angles between the carboxylate groups in the 3' and 4'-positions are 67.24 (15) and 59.98 (17)°, respectively.
authors.forename: Guo-Wei
authors.initials: GW
authors.lastname: Gao
authors.forename: Xiao-Yan
authors.initials: XY
authors.lastname: Ma
authors.forename: Yan
authors.initials: Y
authors.lastname: Jiang
authors.forename: Wei
authors.initials: W
authors.lastname: Chen
authors.forename: Jian
authors.initials: J
authors.lastname: Men