STRUCTURE AND PRELIMINARY ELECTRON-DISTRIBUTION OF COPPER HEPTANOATE FROM ROOM-TEMPERATURE X-RAY DATA

Tetrakis(mu-heptanoato-kO:kO')dicopper [Cu2(C7-H13O2)4], M(r) = 643.4, triclinic, P1BAR, a = 5.170 (1), b = 8.518, c = 19.217 (2) angstrom, alpha = 86.65 (1), beta = 83.60 (1), gamma = 75.46 (1)-degree, V = 813.78 angstrom3. The unit cell contains one dicopper dimer (Z = 1), D(x) = 1.314 g cm-3, mu = 1.350 mm-1 for Mo Kalpha radiation (lambda = 0.70928 angstrom), R(F) = 0.038 for 4861 reflections. The copper-copper distance in the dimer is 2.578 angstrom and each copper is surrounded by five O atoms and one Cu atom in a pseudo-octahedral coordination polyhedron. The copper-copper distance between two dimers is 3.232 angstrom. The hydrocarbon chains are approximately along the c axis, explaining the high value of this parameter. A comparison is made with similar structures of copper alkanoates. Preliminary results of a charge-density study are also given.