Abstract: | On the Existence of Intermediate Reaction Products of Potassium Hydrogen Phosphate and Diphosphate: K2H8(PO4)2P2O7 The crystal structure of K2H8(PO4)2P2O7 has been determined from diffractometer data obtained using MoKα radiation. The space group is Pca21 with a = 9.364(2), b = 7.458(2) and c = 19.560(2) Å, V = 1 366.0 Å3; dm = 2.17(1) g/cm3. Z = 4 · μ(MoKα) = 12.47 cm?1. The structure was solved by direct methods. The crystal structure was refined to R = 0.025 for 416 independent reflexions. Two kinds of PO4 exist and the mean value of P? O is 1.55(2) Å for one and 1.53(2) Å for the other. In P2O7 the angle P? O? P is 135(1)°. The distances P? O of bridge are 1.59(2) and 1.57(2) Å the mean value of P? O in terminals ? PO3 is 1.51(2) Å. The coordination numbers of the potassium ions are nine and eight. K2H8(PO4)2P2O7, compound with mixed anion PO4/P2O7 may be considered as reactional intermediary between acid orthophosphate and pyrophosphate. |