An X-Ray Diffraction Study of the Structure of Guanidinium Aluminum Sulfate Hexahydrate446 - 447

The purposes of the investigation to be described were manifold. An approximate structure of the isomorphous gallium compound has already been reported. 1 The gallium compound with the heaviest metal atom among the isomorphs appeared to be best for establishing the general features of the structure." However, in the hope of finding a closer relation between the structure and its electrical properties, it appeared that a refinement of the structure would be very worthwhile. In such a ease, one would wish to have all of the atoms of more nearly the same scattering power; thus the guanidinium aluminum sulfate hexahydrate (Ci.A.S.H. ) compound seemed most suitable for this purf T h e contribution of H. Katz to this work was made during a period of employment at Bell Telephone Laboratories in the summer of 1959. 425 426 TIIE BELL SYSTEM TECHNICAL JOURNAL, MARCH 1962 pose. Furthermore, this crystal would have the lowest linear absorption coefficient for all practical radiations; the importance of this feature will be discussed later. But probably most important, it was anticipated that the aluminum compound would be the one on which most measurements of various sorts would be made. This has indeed been the case. While our earlier paper 1 was in press, a note'1 appeared in Kristallo(jrajiia which gave an approximate structure for G.A.S.H. and its isomorphs which differed from that reported by us. A check with our data indicated that the structure reported by Varfolomeeva et a/.'1 was incorrect," but this did not mean that, the structure reported by us was necessarily correct.