D. Schwarzenbach
May 1, 1968
Citations
0
Influential Citations
43
Citations
Journal
Journal of Chemical Physics
Abstract
Piperazine hexahydrate, C4N2H10·6H2O, forms monoclinic pseudo‐tetragonal and usually strongly twinned crystals, melting at 44°C. The structure has been determined using x‐ray counter data obtained at room temperature. The space group is P21 / n, with Z = 2, and cell dimensions are a = 6.309, b = 6.323, and c = 14.912 A, β = 94.96°. The hydrogen‐bonded water molecules form puckered layers of almost tetragonal symmetry composed of edge‐sharing pentagons, which are joined into a three‐dimensional framework by hydrogen bonds to the nitrogen atoms of the piperazine molecules. The twin laws are explained as stacking faults of the water layers. The hydrogen atoms are disordered within the water layers and ordered between the oxygen and nitrogen atoms. The bond lengths and angles of the piperazine molecule are normal. The structure is related to the clathrate hydrate structures because of the pentagonal geometry of the water structure.