Literature data pertaining to the crystal chemistry, crystallography, and X-ray powder-diffraction properties of phases reported in the system BaO-CuOx are compiled. Reported phases include BaCuO2−2.12, BaCuO2.26−2.39, BaCuO2.5, Ba2CuO3+x, Ba2Cu3O5+x, BaCu2O2+x, Ba3Cu5O8, Ba3CuO4, BaCu3O4, Ba3Cu2O4+x, Ba5Cu3O6+x, and BaCu2O3. The existence of some of these phases, however, still has to be verified. Most of these compounds are nonstoichiometric in oxygen. Their oxygen content, and in some cases even their crystal structures, vary with oxygen partial pressure. There are also reported indications that the cations Ba and Cu are not stoichiometric in the cubic BaCuO2-type compounds.

A significant feature of the atomic structure of the intermetallic compounds RhAl2.63 (Pearson-Parthé symbol cP(34-5) [notation according to Parthé et al. (1993)], space group P23), IrAl2.75 (cP(34-4), P23) and AuZn3 (cP32, Pm3¯n) is the occurrence of icosahedral clusters. Least squares refined lattice parameters and powder diffraction data are reported for these homeotypic phases.

With a new emphasis on the control of polymorphism in pharmaceutical production, the need for methods to quantify polymorphic forms has arisen. Techniques using X-ray powder diffraction are increasingly being used to characterize the phases of drug substances that exist in multiple crystal forms. Current methods to identify the polymorphic phases in a drug substance include microscopy, infrared spectroscopy, thermal analysis (DSC/TGA), solid state NMR, and X-ray powder diffraction. Of the aforementioned techniques, X-ray powder diffraction provides the most effective approach to identify and quantify the different crystal phases of a pharmaceutical compound. This work is intended as a guide to the characterization and quantification of an organic crystalline system using X-ray diffraction. The approaches suggested are intended to provide assistance not only from an in-process pharmaceutical manufacturing standpoint, but also for routine quality assurance screening of polymorphic drug substances.

X-Ray powder diffraction data for the compound 2,2′,2″-triamino-triethylamine-Ni(II)-di-thiocyanate were obtained by transmission diffractometric methods at 20°C - 22°C. Two data sets were collected with CuKα1 radiation (λ = 1.54056 Å) one with Si as an internal standard (a = 5.430825 Å) and one without.

The deep blue crystals are orthorhombic of space group P212121. Peak positions were corrected by aid of the Si peaks in the first data set. Refinements of lattice constants from indexed reflections yielded the following values: a = 10.8524(18) Å; b = 14.7249(16) Å; c = 8.6511(11) Å; Dx = 1.542 Mg/m3. The second data set was used for a Rietveld refinement. The lattice constants obtained by this method are: a = 10.8451(5) Å; b = 14.7148 Å; c = 8.6447(4) Å.

Quartz in dolostone can be determined quantitatively down to 0.03 weight percent using a standard preparation procedure for the sample and absolute integrated intensity measurements. Measurement reproducibilities of 3.2% were obtained. Calibration curves determined by spiking low-quartz dolostone allowed concentrations of 2.0 weight percent or lower to be established. Higher concentrations of quartz in some related soil samples were determined by comparing the absolute integrated intensity with that obtained from a pure quartz sample prepared in the same manner.

A Rietveld refinement of powder X-ray diffraction data of BiSbO4 is reported. The refined lattice parameters are a =5.4690(2), b =4.8847(3), c = 11.8252(6) Å, and β = 101.131(3)°. The powder data are compared with the PDF patterns designated BiSbO4 (30-177) and SbBiO4 (7-191).

In many experiments on X-ray stress analysis, the tilt angle Ψ shows that for a given peak the integrated intensity function of Ψ is not a constant. In this paper a geometric factor is described which corrects the integrated intensity in asymmetric X-ray diffraction. The defocussing effect, always present in asymmetric X-ray diffraction, reduces the number of diffracted X-ray photons registered by the detector. For a θ/2θ diffractometer, the new correction was found to be dependent on the divergence angle of source and detector slit, the tilt angle Ψ and the Bragg angle θ.

The experimental results corrected with the proposed factor are in good agreement with the theory in limits of acceptable errors.

X-ray powder data are given for glucopyranosylsorbitol, C12H24O11, and glucopyranosylmannitol dihydrate, C12H24O11 * 2H2O. Refined unit cell parameters for glucopyranosylsorbitol are: a=0.9124(4) nm, b=1.1336(5) nm, c=0.7232(3) nm, and β=91.23(4)° in space group P21 and those for glucopyranosylmannitol dihydrate are a=2.2579(15) nm, b=1.0016(5) nm, and c=0.7584(5) nm in space group P212121.

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)°.