Crystal structures of dimetal terephthalate dihydroxides, M 2(C8H4O4)(OH)2 (M = Co, Ni, Zn) from powder diffraction data and DFT calculations

The crystal structure of poly[dihydroxido(μ6-terepthalato)dizinc], [Zn2(C8H4O4)(OH)2] n , was solved and refined using synchrotron powder data, and the structures of the isostructural Co and Ni analogues were refined using laboratory powder X-ray data. The structure of [Co2(C8H4O4)(OH)2] n has been reported previously in space group C2/m, which yields disordered terephthalate anions. Doubling the c-axis of that cell results in an ordered model in space group C2/c. The octahedral MO6 coordination polyhedra of the metal cations share edges, forming chains running parallel to the b-axis direction. These chains share corners (hydroxyl groups), forming layers lying perpendicular to the a-axis direction.