Using the Rietveld profile method, the atomic coordinates and anisotropic temperature factors of KCaF3 were refined. At room temperature, KCaF3 crystallizes in monoclinic B21/m symmetry, with the lattice parameters: a=8.754(2) Å, b=8.765(4) Å, c=8.760(5) Å, β=90.48(3)°, V=672.1(3) Å3, Z=8. The refinement procedure was stopped when RB=0.05 and the Durbin–Watson statistic factor=0.85 had been reached. The structure determined is related to the tilting of CaF6 octahedra of the a−b+c− type, which are responsible for the monoclinic distortion in perovskite crystals.

A new mixed lead thorium phosphate, Pb0.5Th2(PO4)3, has been isolated in the system PbO–ThO2–P2O5. Its crystal structure (monoclinic symmetry, a=17.459(1) Å, b=6.8451(4) Å, c=8.1438(5) Å, β=101.247(5)°, space group C2/c) has been determined from conventional monochromatic X-ray powder diffraction data. The structure is related to the MITh2(PO4)3 structure type. Lead atoms are located in the channels parallel to the c axis, out of the twofold axis for 0.97 Å, and are statistically distributed on a quarter of crystallographic positions. The thermal stability of this material is greater than that of the monazite-type compound PbTh(PO4)2.

The X-ray powder diffraction patterns for two new synthetic calcium uranium (VI) silicate hydrate phases are reported. Ca1.5U6(OH)7O16·7H2O is orthorhombic, space group P*a*, with unit cell a=13.8949(14), b=12.0776(12), c=15.228(3) Å. The structure appears to be related to that of becquerelite. Ca2(UO2)2(Si2O5)3·10H2O was also indexed on an orthorhombic unit cell, a=12.075(3), b=15.406(6), c=26.043(6) Å. The Powder Diffraction File coverage of uranium-containing minerals which could, on the basis of their chemical formula, form in U-containing cements is also reviewed.

The boron and iron for aluminum substitution in the Rb-leucite structure (RbAlSi2O6, ICDD card 38-201) has been examined by sol-gel preparation of different samples along the three compositional joins Rb(X,Y)Si2O6, where X and Y are any two of the elements Al, Fe, B. The compound RbBSi2O6 (a0=12.831 Å) is here described and characterized by X-ray powder diffraction for the first time, while the compound RbFeSi2O6 is reexamined with a more precise determination of lattice parameters and diffraction intensities with respect to ICDD card 31-1189. The lattice parameters and the space groups of different selected terms of the three solid solutions are reported.

A Bi2O3 compound which is unknown to date has been synthesized at 800 °C on a BeO substrate. α-Bi2O3 at 800 °C undergoes a phase transition to a metastable new compound named ω-Bi2O3 which in turn transforms to stable δ-Bi2O3 at 900 °C. X-ray powder diffraction data were collected, indexed, and refined in order to obtain a unit cell (probable space group P1¯: a=7.2688(4), b=8.6390(6), c=11.9698(8) Å, α=87.713(6), β=93.227(6), γ =86.653(4)°. This compound is of interest for the thick films circuits and sensors technology.

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.

Indexed X-ray powder diffraction data are reported for the low temperature tetragonal ZrO2 obtained by crystallization of zirconia gel. The structure was refined by the Rietveld technique on the basis of space group P42/nmc. Refined unit cell dimensions are a = 3.5984(5) Å, c = 5.152(1) Å, V = 66.71 Å3, Dx=6.135 g/cm3, F18=62 (0.012, 24), RP=8.99, Rwp=11.48, RB=3.13.

New powder X-ray diffraction data of davyne, a member of the cancrinite group of minerals, were collected using a rotating anode diffractometer: the hexagonal cell parameters are a=12.6711(3) Å, c=5.3278(2) Å, volume 740.82(4) Å3 (space group P63). The strongest lines are: 3.658(100), 4.790(73), 3.272(70), 2.112(48), 2.438(22), 2.663(19), 1.781(19), and 4.147(17). The new data provide quantitative intensities improved precision in d-spacings and cover an increased 2θ angular range with respect to PDF 20-379. Measured intensities and a simulated pattern are reported together with crystal-chemical considerations.

A Rietveld refinement of X-ray powder diffraction data for orthorhombic BaNd2Mn2O7 is reported. The refined lattice parameters were a=0.5517(5), b=0.5482(3), and c=2.0585(7) nm with space group Fmmm (No. 69).

An in situ high pressure study using energy dispersive X-ray diffraction has been carried out on the polycrystalline high-Tc superconductor, HgBa2CuO4+δ (Hg-1201), to study its phase stability under pressure and also to measure its compressibility and bulk modulus. No evidence of pressure-induced polymorphism was found in the pressure range investigated, i.e., from 0.1 MPa (1 atm) to 5 GPa. The compound exhibited anisotropic elastic properties. The axial compressibility along the c axis was measured to be (3.96±0.35)×10−3GPa−1 and along the a axis (3.42±0.13)×10−3GPa−1, corresponding to an anisotropy ratio of 1.16±0.11. The bulk modulus was determined to be (94.7±4.2) GPa and, assuming a Poisson's ratio of 0.2, Young's modulus was estimated to be (170±8) GPa.

A new occurrence of the poorly characterized mineral, yukonite, (Ca6.44K0.13Mg0.23)(Fe14.68Al0.36)(AsO4)9O15.78·25.5H2O, is described. New powder X-ray diffraction and electron microprobe data are provided for type material from Tagish Lake, Yukon Territory, Canada, and that from the new locality, Saalfield, Thuringen, Germany. New chemical formulae are proposed. The strongest reflections are at 14.1(100), 2.79(60), 3.25(57), 5.58(37), 2.61(20), 1.63(20), and 2.24(11) Å.

X-ray powder diffraction data and refined unit cell parameters for SrTi3Nb4O17, SrTi5Nb4O21, SrTi7Nb4O25, SrTi9Nb4O29, SrTi11Nb4O33, SrTi13Nb4O37, and SrTi15Nb4O41 are reported here. The powder patterns for these oxides suggest that they form a homologous series SrM2n+1O4n+5 (M=Ti, Nb; n=3→9), which is isostructural with the orthorhombic “chemically twinned rutile” series found previously in the K2O-TiO2-Ta2O5 and BaO-TiO2-Nb2O5 systems. The structures are built of corner-sharing slabs of the rutile structure; successive members are generated by adding 2TiO2 to the slab thickness of the previous member. The series crystallizes in space group Cmcm (No. 63), with members exhibiting similar a-, b-dimensions (∼6.6, ∼8.9 Å; respectively), and c-dimensions that linearly increase (by ∼4.4 Å per member) from 20.8 Å for n=3 to 47.1 Å for n=9.