The crystal structure of, and the hydrogen bonding in, the super-acid salt potassium tri-hydrogen di-succinate: a direct solution of the phase problem based on neutron-diffraction measurements*

Abstract

Abstract The title compound, KH3(O2C · CH2 · CH2 · CO2)2, crystallizes in the monoclinic system with four of the above units in a cell with a = 7.404, b = 18.437, c = 9.006 Å, β = 109.6°, and with space group P21/c. The intensities of some 1200 neutron reflections were measured. The structure was solved by a direct method, and refined to R = 8.6% by anisotropic least-squares analysis. The structure embodies infinite chains of hydrogen-succinate anions linked by hydrogen bonds; to these chains, succinic acid molecules are joined each by a pair of hydrogen bonds to corresponding oxygen atoms of successive anions along the main chain.