Powder X-ray diffraction was used to investigate the solid solution range of the Bi14SrxCa12−xO33 series in the Bi–Sr–Ca–O system. Solid solution forms over the range 1≤x≤7 in Bi14SrxCa12−xO33. Experimental X-ray reference patterns of selected members with x=1, 3, 5, and 7 have been prepared for the powder diffraction file (PDF). These phases are monoclinic, C2/m, with cell parameter a ranging from 21.473(4) to 21.868(4) Å, b from 4.3564(9) to 4.3898(9) Å, c from 12.753(2) to 12.962(2) Å, β from 102.91(2)° to 102.79(1)°, and V from 1162.9(3) to 1213.5(3) Å3, respectively. These parameters increase monotonically as Ca is continuously replaced by the larger Sr.

Plane analytical geometry has been used to derive formulas of peak shifts due to specimen geometry and beam divergence of X-ray diffractometers in a Seemann–Bohlin configuration. When the attenuated diffraction below the specimen surface is not considered, peak shifts depend on Bragg angle (θ), incident beam divergence (2α), curvature radius of the specimen surface (r), and the tilt angle of the specimen (ψ). Numerical results show that at any fixed Bragg angle value, the peak shift increases with 2α whatever the combination of r and ψ values are. Moreover, at any fixed value of both Bragg angle and beam divergence, the peak shift depends directly on |ψ| and inversely on |r|. Shifts of peaks have been compared on both goniometer circle (Δ2θS) and focusing circle (Δ2θP). The results show that when ψ>0, then (Δ2θS) is less than (Δ2θP). On the contrary, when ψ<0, then (Δ2θS) is greater than (Δ2θP). Both (Δ2θS) and (Δ2θP) increase when the Bragg angle is decreased under the same fixed set of ψ, 2α, and r values. These peak shifts are so high that lattice strains may be masked at either high values of |ψ| and 2α, or small |r| values.

Two compounds of the elpasolite family (A2BLnX6), Cs2KTbCl6 and Cs2KEuCl6, were obtained {by evaporating to dryness a hot aqueous HCl solution of the appropriate chlorides [Morss etal., Inorg. Chem. 9, 1771 (1970)]} and characterized by powder X-ray diffraction. Title compounds are isostructural with cubic Rb2NaTmCl6 and correspond to the perovskite related structure with space group Fm3m, cell parameters 11.1294(6) and 11.1618(4) Å, V=1378.5(2), and V=1390.5(1) Å3, respectively.

A new phase in the system BaO–MnO–SiO2 obtained by a pyrosynthetic method has been inves- tigated using electron microprobe analysis (EPMA), X-ray powder diffraction (PDA), and trans- mission electron diffraction. The lattice parameters and possible space group of the phase with a general composition BaMnSi2O6 were determined as follows: a=13.896, b=12.261, c=10.781 Å, β=103.47°, space group P21/m, Z=12.

A system enabling X-ray diffraction patterns under controlled conditions of relative humidity and temperature has been devised and combined with an X-ray powder diffractometer. Relative humidity in the sample space is controlled by mixing dry N2 gas with saturated water vapor. Temperatures of the sample and inner wall of the sample chamber are monitored by two attached thermocouples and the information was fed back to the control unit. Relative humidity between 0% and the 95%, and temperature between room temperature and 60 °C can be controlled. All parameters including those for XRD are programmable and the system runs automatically. The function of the system was checked by recording the XRD patterns of montmorillonite (a clay mineral) and NaCl under increasing and decreasing relative humidity.

A conventional vertical powder diffractometer has been adapted to allow the collection of high-resolution, single-wavelength diffraction data using Co, Cu or Mo radiation. The major modifications are (i) incorporation of an incident beam focusing monochromator attached to the tube shield, (ii) a variable tilt angle of the tube shield to provide a horizontal beam path through the diffractometer (for ease of alignment), (iii) mounting of the entire diffractometer on a single, very stable base-plate, with micrometer-controlled adjustment of the orientation, (iv) inclusion of a knife-edge, micrometer-controlled focusing slit, and (v) use of a range of Soller slits with acceptance angles down to 1.5° 2φ. The performance of the instrument compares favourably with conventional non-monochromated diffractometer data collected from SRM660 LaB6 and monoclinic ZrO2. In particular, the peaks are more symmetric and have narrower widths, and the peak-to-background ratio is much higher, leading to much superior resolution and profile shapes for structure solution and Rietveld refinement.

The X-ray powder diffraction pattern for the title compound is reported in the range 10<2θ<60°. The sample was purified by recrystallization and was indexed using the program DICVOL91 and TREOR90. Refined unit parameters for the orthorhombic system (Pnma or Pn21a) are: a=13.7098(8) Å, b=10.7153(7) Å, c=6.9473(4) Å, V=1020.59 Å3, Z=4, Dx=2.50 g cm−3. M20=49, F30=93(0.0075, 43).

The X-ray diffraction data for the single phase UAl4 are reported. The data were obtained with a Huber–Guinier diffractometer with MoKα1 radiation. The unit cell of UAl4 is orthorhombic (space group Imma) with lattice parameters a=4.396 Å, b=6.251 Å, and c=13.699 Å.

p-nitrophenol, C6H5NO3, and disophenol, C6H3I2NO3, have been investigated by means of X-ray powder diffraction. The unit cell dimensions were determined from diffractometer methods, using monochromatic CuKα1 radiation, and evaluated by indexing programs. The monoclinic cell found for p-nitrophenol was a=6.159(2) Å, b=8.890(2) Å, c=11.770(2) Å, β=103.04(2)°, Z=4, space group P21 or P2l/m, Dx=1.469 Mg/m3. The monoclinic cell found for disophenol has the dimensions a=8.886(1) Å, b=14.088(2) Å, c=8.521(1) Å, β=91.11(1)°, Z=4, space group P2, P2, Pm or P2/m, Dx=2.438 Mg/m3.

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.

Gamma-phase lithium aluminate (LiAlO2) is a ceramic powder used in molten carbonate fuel cells (MCFCs) and in other nuclear and ceramic applications. Upon exposure to water vapor and carbon dioxide at 25 °C, we have observed that gamma-LiAlO2 converts to lithium aluminum carbonate hydroxide hydrate, Li2Al4(CO3)(OH)12·3H2O(LACHH) and Li2CO3. The conversion was observed by X-ray diffraction (XRD) and carbonate analysis. An equation for the conversion is given, and the morphology is determined by scanning electron microscopy. A high-temperature XRD study and thermogravimetric/differential thermal analysis (TGA/DTA) showed that LACHH decomposes at 250 °C. The decomposition products of LACHH and Li2CO3 react to form first alpha-LiAlO2 and then gamma-LiAlO2 at temperatures of 650 and 1000 °C, respectively.

The crystal structure of Cr2[Ni(CN)4]3·10H2O has been determined on X-ray diffraction powder data by means of the Rietveld method. The starting model was based on the isomorphic, disordered structure of Mn3[Co(CN)6]2·12H2O. At room temperature the crystal is cubic, F4¯3m, a=10.097(6) Å, V=1029.4(5) Å3. The structure is disordered and contains 1.33 formula weights per unit cell. The Ni and Cr ions are coordinated by N and C atoms, respectively, forming octahedra linked by CN groups. The water molecules replace partly the chromium, carbon, and nitrogen positions in the crystal. The final R values are: Rwp=0.032 (Rexp=0.023), RB=0.088, and DW-Stat.=1.31 (DWexp=1.8).