Bragg–Brentano X-ray powder diffractometry data and refined unit cell parameters are reported for a synthetic sample of dolerophanite, copper (II) oxysulphate [Cu2O(SO4)], prepared by heating AR copper (II) sulphate anhydrate in a muffle furnace at 725 °C. The data are compared with (i) two Debye–Scherrer patterns published by Mrose [Am. Mineral. 6, 146–153 (1961)]—for a synthetic sample and for a natural dolerophanite, the latter being pattern 13–189 in the ICDD Powder Diffraction File and (ii) a Debye–Scherrer pattern for a synthetic dolerophanite described by Borchardt and Daniels [J. Phys. Chem. 61, 917–921 (1957)]. A calculated pattern is also presented for the crystal structure of dolerophanite described by Effenberger [Monatschefte fur Chemie. 116, 927–931 (1985)]. The measured and calculated patterns reported here show reasonable internal consistency for both line positions and intensity data. While the agreement between these results and the data sets of Mrose is sound in terms of line positions, there is substantial disagreement overall between the intensity values given by the authors and those of Mrose. There is closer agreement between the intensities from the current study and those of Borchardt and Daniels.

The Powder Diffraction File of crystallographic data has been converted from printed data cards to a computer database. Extensive testing, review, and editing of the database were completed, the history and first stages of which are presented. Computer programs used to create and analyze the database are described.

The unit cell dimensions of minerals in the smectite group, regular and random mixed-layer groups, and halloysite shown in the Mineral Powder Diffraction File (1986) have been refined by least-squares analysis in the hexagonal system with a primitive lattice with indices restricted to hk or 00l reflections. Trioctahedral minerals have larger a unit-cell dimensions than dioctahedral minerals.

The crystal structure of α-CoSO4 has been refined by the Rietveld method from X-ray powder diffraction data. The structure is orthorhombic, space group Pnma, a = 8.6127(4), b = 6.7058(3), c = 4.7399(2) Å, V = 273.75(3) Å3. Final RB = 2.41%, RP = 5.24%, RWP=6.66%, RWP (expected) =5.74% (WP =weighted profile). The structure consists of edge-sharing octahedral chains parallel to [010] interconnected by SO4 tetrahedra.

X-ray powder diffraction data are reported for the [(NH4)3Al1−xFex/2Crx/2(C2O4)3]·3H2O solid solution. The crystal system is triclinic with space group P1. Refined unit-cell parameters are given for the compositions x=0.10, 0.50 and 0.80.

Crystal data and results of structure refinements for MnSi are reported. The material is cubic, P213, with a = 4.5603(2) Å, Vd = 94.84(1) Å3, Z = 4, Dx = 5.815 Mg/m3. Intensity data were obtained from a Stoe transmission type diffractometer equipped with a position sensitive detector. CuKα1 radiation, λ = 1.5405981 Å was employed. Germanium was used as an internal standard for the determination of the lattice constant (aGe= 5.6582 Å). The structure was refined by the Rietveld method by aid of three different programs.

The heterocycle of a functionalized 2-imidazoline, C15N2OH18, was obtained by reaction when 2-bromo, 2-alkenoïc ketone was allowed to react with a monosubstituted benzamidine. The compound presents a R*R* configuration. X-ray powder diffraction data have been obtained from single multifaceted brown crystals prepared at 273 K in benzene with triethylamine as catalyst. Chemical analysis gives a purity better than 99%. This compound crystallizes in the monoclinic space group P21/c [14]. The cell parameters were determined by employing single-crystal diffraction methods (Bragg and precession patterns) and were refined from accurate powder diffractometer data recorded at T = 293 (1) K.

A unique file structure and search algorithm have been developed for the purpose of obtaining matches between experimental electron diffraction and qualitative energy dispersive X-ray compositional data from an unknown crystalline phase and the reference data in the JCPDS Powder Diffraction File. The reference data for over 32,000 inorganic compounds from sets 1–33 were compressed and stored in binary format as bit pattern maps. The entire data set and searching programs require less than 4 Mbyte and retain the precision appropriate for electron diffraction analysis. The search algorithm, written in both RT-11 FORTRAN and Flextran, is based on pattern matching between bit maps obtained for the unknown and reference compounds for both composition and diffraction data. Special attention is given to double diffraction effects commonly encountered in electron diffraction analysis. The programs run on an interactive basis on a microcomputer dedicated to the X-ray energy dispersive spectrometer on an analytical electron microscope. A typical search takes about 15 seconds to run and extracts about 10–15 different compounds.

In conventional multiphase Rietveld refinement, now being used for quantitative phase determination, the crystal structure of each phase needs to be known in order to generate a calculated standard pattern of the phase to be refined against the measured XRD pattern. This is a disadvantage when the structural data for a phase are imperfect or unknown and may prevent an analysis.

A method is given whereby a phase with an imperfectly known or unknown crystal structure can be included in a multiphase Rietveld refinement, with other well-characterised phases, by use of an empirical or “observed” hkl file for that phase, with the SIROQUANT software package. The amplitudes 1F(hkl)1 in the empirical hkl file of the phase generate a reference profile for it which agrees with a measured standard pattern of the phase. Methods are given for the creation and scaling of empirical or “observed” phase hkl datasets. The Rietveld variable parameters (preferred orientation, linewidth, lineshape and unit cell) are refinable in the usual way for a phase with an empirical hkl dataset.

The X-Ray Powder Data File (XRPDF) enables one to identify the compounds in a sample. More often than not, however, a semi-quantitative analysis is wanted. Visual inspection of the pattern may give a vague impression of the composition, but the errors of such a result are usually not within reasonable limits. Clearly a less subjective and more accurate method is wanted. If the necessary data are printed on the cards, such a method will greatly enlarge the usefulness of the File.