STRUCTURE OF BARIUM ALPHA-D-RIBOFURANOSE-5-PHOSPHATE PENTAHEMIHYDRATE - A REINVESTIGATION

Ba2+.C5H9O8P2-.5.5H2O, M(r) = 464.52, monoclinic, C2, a = 15.469 (9), b = 8.622 (5), c = 12.865 (8) angstrom, beta = 118.33 (5)-degrees, V = 1510 (2) angstrom 3, Z = 4, D(m) = 2.047, D(x) = 2.043 (2) g cm-3, lambda(Mo K-alpha) = 0.71069 angstrom, mu = 28.8 cm-1, F(000) = 916, T = 300 (2) K, R = 0.030 for 6055 hkl and hklBARBARBAR non-zero reflections. The P-O(ester) bond is 1.616 (2) angstrom. Distortions from tetrahedral geometry of the phosphate group are similar to those observed in other doubly ionized phosphate esters. The conformation of the alpha-D-ribofuranose ring is 2E. The torsion angles P-O(5)-C(5)-C(4), O(5)-C(5)-C(4)-O(4) and O(5)-C(5)-C(4)-C(3) are 170.9 (4), -67.9 (4) and 52.6 (4)-degrees, respectively. Each Ba2+ cation is surrounded by ten O atoms (one of them is disordered) at distances of 2.730 (4)-3.338 (3) angstrom.