Crystal Structure, Synthesis, and Properties of tri-Calcium di-Citrate tetra-Hydrate [Ca3(C6H5O7)2(H2O)2]•2H2O

From hydrothermal synthesis needle-shaped crystals of [Ca-3(C6H5O7)(2)(H2O)(2)]center dot 2H(2)O were obtained. The crystal structure was determined by single-crystal X-ray experiments and confirmed by powder data (P (1) over bar (no. 2) a = 5.9466(4), b = 10.2247(8), c = 16.6496(13) angstrom, a = 72.213(7)degrees, beta = 79.718(7)degrees, gamma = 89.791(6), V = 947.06(13) angstrom(3), Z = 2, R1 = 0.0426, wR2 = 0.1037). The structure was obtained from pseudo merohedrically polysynthetic twinned crystals using a combined data collection approach and refinement processes. The observed three-dimensional network is dominated by eightfold coordinated Ca2+ cations linked by citrate anions and hydrogen bonds between two non-coordinating crystal water molecules and two coordinating water molecules.