Diguanidinium hydrogenarsenate monohydrate and its deuterated analogue: Vibrational, DSC and X-ray investigations

The crystal structure of diguanidinium hydrogenarsenate monohydrate has been found to belong to the P4¯21/c space group of the tetragonal system, with Z = 8, a = 17.114(2) Å, c = 7.3500(10) Å. In this complex, a network of hydrogen bonds links water molecules and hydrogenarsenate ions. The hydrogenarsenate ions form hydrogen-bonded chains along the crystallographic c-axis. Detailed vibrational studies have been carried out (FTIR and FT-Raman on powder samples, polarized FTIR microscope on a small single crystal at room temperature). The vibrational spectra are discussed in relation to the crystal structure. Calorimetric (DSC) studies have been performed, but no phase transition was found in the temperature range 100–350 K.