Journal of Applied Crystallography

Mathieson, A. M.

doi: 10.1107/S0021889875011338pmid: N/A

Lazarini, F.

doi: 10.1107/S0021889875011314pmid: N/A

Single crystals of α‐beryllium (II) bromide were grown by sublimation. Lattice parameters were determined from Weissenberg and precession photographs. It was confirmed that α‐BeBr2 and α‐BeCl2 are isomorphous.

Mitra, G.B; Mathur, B.K

doi: 10.1107/S0021889875011223pmid: N/A

Cavero‐Ghersi, M. C.; Durif, A.

doi: 10.1107/S0021889875011272pmid: N/A

Chemical preparations and crystal data are described for five new tetrametaphosphates: CaK2P4O12, PbK2P4O12, PbRb2P4O12, Pb(NH4)2P4O12 and PbTl2P4O12. All of them are tetragonal and isotypic with SrK2P4O12. The space group is I with Z = 2.

Wallace, C.A; Ward, R.C.C

doi: 10.1107/S0021889875011235pmid: N/A

The use of X-ray diffraction for identification and analysis of thin epitaxic layers, grown on a single-crystal substrate of alien material, is often complicated by the predominant diffraction of the substrate, which may obscure that of the layer, and the incidence of `substrate-imposed' twinning. Techniques have been devised whereby control of the incident radiation spectrum and the angles of diffraction enables the X-ray diffraction pattern of the layer to be enhanced. Information concerning the identity of the material and its orientation with respect to the substrate surface is readily obtained, followed by analysis of the epitaxic relationships and twinning modes. The use of X-ray intensity data is discussed, with particular reference to the determination of crystallographic polarity, and a method for the precise measurement of the lattice parameter of thin films is presented, which is applicable to the characterization of solid solutions.

Allen, M.W; Lipson, H

doi: 10.1107/S0021889875011375pmid: N/A

Niimura, N.; Tomiyoshi, S.; Takahashi, J.; Harada, J.

doi: 10.1107/S0021889875011260pmid: N/A

An application of the time‐of‐flight neutron diffraction technique to an investigation of the nature of the extinction effect in a single‐crystal specimen is given. It is shown that the wavelength dependence of the extinction can be easily obtained by changing the scattering angle. An estimation of the extinction factor for a CuCl single crystal is given as an example and a comparison of the results with recent extinction theory (Becker & Coppens. Acta Cryst. (1974). A30, 129–147; 148–153) is made.

Villagrana, R. E.; Garth, J. M.

doi: 10.1107/S0021889875011259pmid: N/A

The application of computer image processing to enhance a diffuse scattering signal in an electron diffraction pattern is described. In order to illustrate this technique, a diffraction pattern from a rapidly quenched CuPt specimen was processed.

Langford, J. I.

doi: 10.1107/S0021889875011399pmid: N/A

Averbuch-Pouchot, M.T; Durif, A

doi: 10.1107/S0021889875011284pmid: N/A

The chemical preparation and crystal data for a new zinc tripolyphosphate, Zn5(P3O10)2.17H20. are reported. The unit-cell data of this new salt are a = 10.766(8), b = 10.316(8), c = 8.525(5) A, = 111.39(5), = 115.08(5), = 70.19(5)Degrees.