Effect of the anion on cation chain geometry in hexamethylenediammonium salts

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Ethane-1,2-diammonium dibromide: a redetermination at 100 K

In the redetermined [for the previous study, see Søtofte (1976 ▶). Acta Chem. Scand. Ser. A, 30, 309–311] crystal structure of the title compound, C2H10N2 2+·2Br−, the H atoms have been located and the hydrogen-bonding scheme is described. The ethane-1,2-diammonium cation lies over a crystallographic inversion centre and straddles a crystallographic mirror plane with the C and N atoms in special positions. In the crystal, the cations and anions are linked by N—H⋯Br and N—H⋯(Br,Br) hydrogen bonds, which generate various ring and chain motifs including an R 10 5(32) loop

Butane-1,4-diammonium bis(perchlorate)

The butane-1,4-diammonium cation of the title compound, C4H14N2 2+·2ClO4 −, lies on a special position of site symmetry 2/m, whereas the perchlorate anion is located on a crystallographic mirror plane. An intricate three-dimensional hydrogen-bonding network exists in the crystal structure with each H atom of the ammonium group exhibiting bifurcated inter­actions to the perchlorate anion. Complex hydrogen-bonded ring and chain motifs are also evident, in particular a 50-membered ring with graph-set notation R 10 10(50) is identified