Aarón Pérez-Benítez, Luis E Hernández Márquez, Rosa Elena Arroyo-Carmona, Sylvain Bernès
The crystal structure of the title salt, C4H13N5 2+·2Br-, is reported in space group P21/c, with Z = 4. Unexpectedly, this crystal is not isomorphous to the dichloride analogue, which has been reported in space group P21 (Z = 2). This originates from the shift of one halide anion in the asymmetric unit, which modifies the network of N-H⋯halide hydrogen bonds. For the here-reported structure, centrosymmetric R 4 2(8) ring motifs are formed, affording a one-dimensional structure along [100], and the network is further expanded to a three-dimensional structure including larger ring motifs. This report is an example of a routine refinement carried out using now well-established techniques of quantum crystallography.