Occasional gaps in diffraction arcs are to be expected on “powder films” obtained with the Gandolfi X-ray camera, particularly when the specimen is a single crystal of low symmetry. The geometrical limitations of the method were succinctly and elegantly stated by the worker whose name the camera bears, in work published a quarter of a century ago. Gandolfi also stated a meansibr amelioration of the missing reflections “problem” Numerous authors have made reference to such discrepancies in the intervening period. These minor difficulties notwithstanding, the Gandolfi camera remains a powerful tool for materials analysis.

Crystal data are given for synthetic mixed bariumstrontium sulfates, and a powder pattern for (Ba0.50Sr0.50)SO4 is presented. Taken with previously published data for the end-member sulfates, we verify the nonlinear behavior of the unit-cell edges with composition, and present tables of interpolated data from which d-spacings for intermediate compositions can be calculated. The use of these data for analysis of complex natural samples by use of the 121 peak is described.

Fifteen reference patterns of oxide ceramics are reported. Included in the fifteen reference patterns are data for nine high critical temperature superconducting oxide and related phases Ba2Cu3ErO7, Ba3.2Cu1.7Er0.8O6.1·xCO2, Ba2Cu3HoO7, Ba2Cu3(Pr0.5Y0.5)O7, Ba3Dy4O9, Ba3Yb4O9, (Ba0.6Sr0.4)2Cu3YO7, (Ba0.8Sr0.2)2Cu3YO7, and CuNd2O4. The general methods of producing diese X-ray powder diffraction reference patterns were described previously in this journal (Vol. 1, No. 1, pg. 40 (1986)). The symbols used in diis article are defined in the PDF cards.

Since the discovery of the superconductivity in Ba2YCu3 O7-x, the system Ba-Y-Cu-O has generated vast interest. The presence and the properties of the intermediate phases were examined, and the existence of the BaY2O4 phase was confirmed.

We have determined the crystal structure of this material from powder data; it is orthorhombic, Pnma (no 62) with a = 10.394(3) Å, b = 3.450(1) Å, c = 12.113(4) Å, isotypic with SrY2O4 (CaFe2O4-type). The observed and calculated intensity values are reported together with the powder diffraction data, obtained both by Guinier and diffractometer methods.

Palladium tetrammine dichromate, [Pd(NH3)4]Cr2O7, was obtained by precipitation from [Pd(NH3)4]Cl2·H2O and (NH4)2Cr2O7. The X-ray diffraction pattern of this compound corresponds to a new phase, which was indexed in the triclinic system, but on a cell that should be considered as preliminary. From the chemical analysis and the X-ray absorption experiments at both K-edges of Pd and Cr, we conclude that the surrounding of these atoms is kept during formation.

Three members of the family [CuC15H11N3)X2]·nH2O [X−=NCO (n=1), NCSe and N3 (n=ø)], C15H11N3=2,2′:6′,2″ – terpyridine (terpy), have been prepared by reaction in solution. Crystal data determined widi the aid of single crystal methods, powder diffraction data, and densities determined by flotation methods are presented.

High quality powder diffraction data were obtained from a specimen containing inseparable impurities, by using single crystal precession photographs to explore all possible reflections for the mineral being studied. In this manner it is acceptable to ignore weak reflections that do not index on the unit cell and that are not observed on the single crystal photographs. Triphylite is given as an example.

New X-ray powder data for CaWO4 (synthetic scheelite) are presented and compared with the current PDF patterns and with a calculated pattern.

Three isotopic orthovanadates MTh2 (VO4)3 with M = K, Rb, Cs have been syndiesized by solid state reaction. Single crystals of K Th2 (VO4)3 and Rb Th2 (VO4)3 were obtained. These compounds are isotypic with the corresponding orthophosphates: monoclinic, space group C2/c, Z = 4. Unit-cell parameters for die diree compounds were determined. Powder diffraction data for each phase are reported.

Zr(MoO4)2 molybdate has been synthesized by solid state reaction. Single crystals were obtained by hydrothermal synthesis. Corrected crystal data are: monoclinic, a = 11.4309 (3), b = 7.9376 (2), c = 7.4619 (2) Å and β = 122.323 (2)°, V = 572.13 (6) /cm3 (5), Dx = 4.770 g/cm3. Powder diffraction data are reported.

Indexed powder diffraction patterns and related crystallographic data are reported for tetracycline-urea tetrahydrate and tetracycline hexahydrate, neither of which is represented in the X-ray Powder Diffraction File. Objective evaluation of the data indicates high precision of d-spacings and unit-cell parameters, intensities that are acceptably reproducible, sensitivity for low intensity reflections, good resolution of closely spaced reflections, and close correspondence with calculated patterns.

Crystallographic and X-ray powder diffraction data were derived from a sample of (Na0.5Bi0.5)TiO3 synthesized by standard ceramic techniques. The powder data were indexed on a monoclinic cell having the space group P2 or Pm, which differed from a previously reported rhombohedral cell.

Thirteen isotypic tellurates having the stoichiometries MIBaNbTe2O9 and BaNbTe2O9, with MI = Li,Na,K,Rb,Ag and MII = Mg,Ca,Sr,Ba,Cu,Zn,Cd,Pb, have been synthesized by solid state reaction. Single crystals of KBaNbTe2O9 were obtained. The compounds crystallize in the orthorhombic space group P212121 [19]. Unit-cell parameters for the 13 compounds and powder diffraction patterns for three representative compounds, KBaNbTe2O9, Ba1.5NbTe2O9 and Cd0.5BaNbTe2O9, are given.

New X-ray powder data and a refined cell for mellite are presented and evaluated in comparison with the current PDF 28-2001.

Nickel Cimetidine Chloride, Ni(C10H16SN6)2Cl2·2H2O has been investigated by means of X-ray powder diffraction. Unit cell dimensions were determined by indexing programs, from diffractometer data obtained with copper radiation. A primitive monoclinic cell was found: a = 11.836(3)Å, b = 13.322(5)Å, c = 10.487(2)Å, β = 113.08 (2)°, Z = 2, Dx = 1.462 g/cm3, M.W. = 670.32. These data are consistent with values reported in the literature for other cimetidine complexes.

Wolfeite (Fe0.59Mn0.40Mg0.01)2PO4(OH) from the Hagendorf-Sud pegmatite, Bavaria, Federal Republic of Germany, yields unit-cell parameters of: a = 12.319(1), b = 13.280(2), c = 9.840(1) Å and β = 108° 24(1). Dmeas. = 3.82(2); Dcalc. = 3.88. An indexed powder diffraction pattern is given.