crystal data
Several guanidinium salts have been studied since, because they contain six hydrogen atoms per unit charge, they are likely to contain multiple hydrogen bonding systems [see e.g. Adams & Small (1974). Acta Cryst. B30, 2191–2193], which are of interest in themselves and are also likely to cause stabilization of the structure. The crystal data of a range of salts were collected and are given. Space group and approximate cell dimensions were obtained from oscillation and Weissenberg photographs. Powder diffraction data [0° to 60° (2θ using Cu Kα)] were indexed and the cell parameters refined using the programs PIRUM of Werner [Program No. 1, World List of Crystallographic Computer Programs (3rd. ed.): J. Appl. Cryst. (1973). 6, 309–346] and CELFIT of Bracher [UKAEA Research Report, AERE-R5412 (1967)].