The crystal structures of the acid salts of some dibasic acids. Part IV. Potassium hydrogen succinate: X-ray and neutron-diffraction studies

Abstract

Potassium hydrogen succinate crystallises in the monoclinic system with Z= 4 in a cell with a= 6·102, b= 6·041, c= 15·895 Å, β= 91·8°, and space group I2/a. The structure has been determined with 1272 independent X-ray reflexions and refined to R 7·5%. A refinement has also been carried out using a less complete set of neutron data. This acid salt proves to be of Type A₂: hydrogen succinate anions, themselves centrosymmetric, are linked into infinite chains by hydrogen bonds across crystallographic two-fold axes. These hydrogen bonds are ‘very short’, with O H O 2·446(4)(X-rays), and 2·444(8)Å(neutrons). The i.r. spectrum is of Hadži's Type (ii). The hydrogen bond may plausibly be regarded as symmetrical.