Cd3(BO3)2 was prepared by a solid state reaction between B(OH)3 and Cd(OH)2 at low temperatures ranging between 523° and 623° and at a pressure of 10−4 – 10−5 Hg mm. The crystal structure has been refined by Rietveld analysis of X-ray powder diffraction data. The compound crystallizes in the orthorhombic system, space group Pnnm, Z = 2, with cell parameters of a = 5.967(5) Å, b = 4.78 (0) Å and c = 9.009(5) Å.

X-ray powder diffraction data for Bi2Mo3O12·nH2O (n = 4.75) were obtained. The crystal system was determined to be monoclinic with space group P21or P21/m. The unit cell parameters were refined to a = 6.334(2) Å, b = 11.593(2) Å, c = 5.777(2) Å, and β= 113.166(8)°.

The crystal structure of Tl4V2O7 is solved ab-initio from powder diffraction data collected in Debye-Scherrer geometry using an Inel X-ray Position Sensitive Detector. The structure has been determined from Rietveld analysis in space group ml, Z = 1, with a = 5.9388(2)Å and c = 7.7322(3)Å. The structure of Tl4V2O7 is built up from isolated V2O7 groups aligned along the trigonal c axis. Thallium atoms alternate along a 3-fold axis. The presence of stereochemically active lone pairs is demonstrated and their positions are calculated using a self-consistent electrostatic model. The influence of sample absorption is briefly discussed and the results are compared with those obtained in Bragg-Brentano geometry using flat-plate specimen.

Three members of the family [Cu(C14H15N3)X2]·nH2O [X = N3(n = 1); NCS and Br(n = 0)], C14H15N3, = N-(2′-(6-methyl) pyridyl) methylene-2-(2′-pyridyl)ethylamine)] (pymep), have been prepared by reaction in solution. Crystal data determined with the aid of single crystal methods, powder diffraction data, and densities determined by flotation methods are presented.

X-ray powder diffraction data for the compound 2,2′,2″-triaminotriethylamine-trihydrochloride, N-(CH2−CH2−NH2)3 (HCL)3 are reported. The crystals are cubic and the space group is P213 with a = 10.8734(12) Å. Dx = 1.320Mg/m3. The data were obtained both by photographic and diffractometric methods.

The volume compression of BaNd2CuO5 (brown phase) and BaLu2CuO5 (green phase) have been measured to 8.67 and 9.23 GPa, respectively, utilizing a diamond anvil high-pressure cell and energy dispersive X-ray powder diffraction. The pressure dependence of the volume of the orthorhombic BaLu2CuO5 and tetragonal BaNd2CuO5 unit cell, as determined by a least-squares fit of the data, are both linear and follow the equations of V=−1.615P+260.62 Å3, and V=−1.9001P+476.92 Å3, respectively. While linear compressions of the unit cell parameters of BaNd2CuO5 exhibit isotropic compressive behavior within our experimental error, BaLu2CuO5 shows somewhat anisotropic compressibility behavior. From the observed data, the bulk modulus of BaNd2CuO5 is determined to be 161±8 GPa and the Young's modulus is estimated to be 193 ±9 GPa. For BaLu2CuO5, the corresponding bulk modulus and the Young's modulus are estimated to be 251±13 GPa and 301±16 GPa, which are significantly greater than those of the brown phase and the high-Tc superconductor Ba2YCu3O6+x. No evidence of a pressure-induced phase transformation was found in either compound in the pressure range studied.

The resemblance between powder patterns because of similarity of crystal structures is well known and widely used. This phenomenon facilitates the determination of unit cells and is frequently used to predict crystal structures of new substances. At present the matching of diffraction analogues is done mainly by hand. Some approaches have been considered in this paper for applying a computer to the problem. Four numerical criteria for resemblance of powder patterns are suggested. Powder patterns are matched with patterns in a database by making use of a computer program based on these criteria.

The procedure results in a short list of powder patterns to be examined by the expert. The efficiency of the program is illustrated by examples of calculations for substances of both high and low symmetry. The search system may find an important application in X-ray powder diffraction analysis for the identification of solid solutions, of substances documented under unusual conditions, of structure analogues and for classification of patterns in a database.

New powder X-ray diffraction data of adenosine C10H13N5O4 were reported: cell parameters area=4.8386(4) Å, b=10.2919(4) Å, c=11.8555(4) Å, β=99.298(5)°, volume 582.63(4)Å for the monoclinic space group P21. The strongest lines are: 7.723 (100), 5.085 (50), 5.851 (45), 4.710 (11), 3.881 (10), 3.899 (9), 3.292 (9), and 3.261 (9). Reported intensities are validated by Rietveld analysis. The data consist of measured positions and intensities and cover an angular range up to 75° 2θ and are significantly better than PDF 35-1977. Experimental, calculated, and difference patterns are also reported.

The ternary compound YAg0.4Ga1.6 has the CaIn2-type structure. The only variable positional parameter z was determined by graphical methods from visual observations of intensities on a Debye-Scherrer pattern. Cu or Ni substitutions for Ag also result in a ternary CaIn2-type structure.