By means of X-ray single crystal Weissenberg photographs, the crystal of the low-temperature solid form of 2-methyl-2-nitro-propanol, (CH3)2C(NO2)(CH2OH), has been determined and found to be of the monoclinic type, space group P21/c. The cell constants were refined from X-ray powder diffraction data: a=6.195(3) Å, b=19.116(7) Å, c=16.598(7) Å, and β = 90.12(2)° with Z = 12. The indexed pattern at 293 K is given.

A novel algorithm has been developed for obtaining directly the applicable indices hkl for any interplanar spacing, dobs±Δdobs, of a triclinic phase with known unit cell parameters. This method is particularly useful for indexing back reflections for triclinic phases with unit cell volumes greater than 500 Å3.

X-ray powder diffraction data for buckminsterfullerene, C60 are reported. The crystal structure is a face-centered cubic unit cell with a = 14.165 (1) Å. The reference intensity ratio (I/Icor) is 2.20.

The silicate compound, K3Nb3O6Si2O7, has been synthesized by solid-state reaction. Single crystals were obtained; they crystallized with the hexagonal space group P2c. Refined unit-cell parameters are: a = 9.0377(3), c=8.0465(7)Å, V=569.18(5)Å3, Z=2, Dm = 3.84(4), Dx=3.851. Powder diffraction data are reported.

X-ray powder diffraction data are reported for a series of isomorphous compounds of [Ln2(CrO4)3(H2O)5]·2H2O, where Ln=La, Pr, Nd, Sm, or Eu. The compounds crystallize in monoclinic space group P21/c (No: 14) with Z=4. Refined unit cell parameters and indexed powder diffraction patterns are given.

Two new thiophosphates with an original structure corresponding to formula ATi2(PS4)3 (with A=Na,Ag) were synthesized by solid-state reaction. The two compounds are isostructural, hexagonal space group P6cc, Z=8. A single crystal of NaTi2(PS4)3 has been studied. Unit-cell parameters were determined for NaTi2(PS4)3 and AgTi2(PS4)3, respectively: a= 19.9131(6) Å, c= 11.5542(7) Å, V=3967.8(3) Å3 and a=20.0146(8) Å, c= 11.5467(8) Å, V=4005.7(4) Å3. Powder diffraction data are reported.

Recent X-ray single-crystal diffraction studies have shown that CuFeSe2 crystallizes in the tetragonal system with space group P2c [, No. 112], Z = 4, with a =5.530(1) Å and c = 11.049(2) Å, c/a = 1.998. This material had been reported as pseudocubic with a =5.53 Å. The purpose of this paper is to present new X-ray powder diffraction data for CuFeSe2 and to compare the results with those reported for eskebornite, a mineral with ideal chemical composition CuFeSe2, and with those obtained from single-crystal structure data.

Ba0.5+x/2Zr2P3−xSixO12 or BaZPS compounds were synthesized by the sintering of powders formed by a solid-state reaction. The cell parameters of Ba0.5Zr2P3O12 and Ba0.5875Zr2P2.825Si0.175O12 were determined from X-ray diffraction (XRD) data based on the (#148) space group with hexagonal setting. The cell parameters were found to increase with increasing Si content in BaZPS.

Sm(OH)2NO3, was prepared by hydrolysis of the corresponding nitrate, leading to a product which is insoluble in water. IR-spectroscopy showed a comparison with the analogous Gd-compound. The temperature of decomposition to SmONO3 is below 573 K. The structure was refined by the Rietveld technique in space group P21, (Z=2), a=6.3852(3) Å, b=3.7784(2) Å, c=7.7402(3) Å, β=97.572(3)°, V=185.11 Å3, Rp=4.9, Rwp=6.3, RB=4.0. The compound is isotypic with Ln(OH)2NO3 (Ln=Pr,Nd,Gd). Infrared spectra and thermal decomposition data are also given for the Gd phase.

A new method for the quantification of montmorillonite by full-profile Rietveld analysis of the XRD profile is presented. A measured standard XRD pattern of Algerian bentonite was used to construct a universally applicable montmorillonite (hkl) file for use with a P.C. based Rietveld XRD quantitative analysis system, SIROQUANT. “Universal” means that the standard file can be used for montmorillonites from other localities. The validity of the montmorillonite standard profile was tested with weighed mixtures of quartz and different standard montmorillonites. The results show the montmorillonite observed (hkl) file is generally applicable (i.e., universal), and can be used to quantify montmorillonite in any mineral without modification or chemical treatment of the sample. Two halfwidth functions were used for the montmorillonite, corresponding to the sharp (hk0) and broad (hkl) classes of reflections. A March preferred orientation parameter for montmorillonite was also refined.

Use of the overlap integral in X-ray diffraction (XRD) powder pattern recognition of crystalline materials is presented. The mathematical expression, derived specifically for diffraction data, provides a measure of similarity between two patterns. Each pattern is represented by a normalized mathematical function. The index of similarity, or overlap integral, indicates how faithfully the two functions overlap and ranges from zero to unity, reaching the latter limit when the two patterns become identical.

A computer program for phase identification using powder diffraction data is presented. It works with a small database containing the unit-cell dimensions and Bravais lattice for chosen classes of inorganic substances. The algorithm works for single phase samples and such samples in which a single phase dominates. During the search, the peak positions generated using the reference unit cells are compared with the experimental ones. Unit-cell constants of all obtained solutions are (optionally) immediately refined. Application examples show that the method gives as possible solutions those database entries for which the cell dimensions differ from the investigated sample by not more than about 0.05 Å. These entries may include the true phase or isotypical phases unless the imposed chemical constraint does not exclude them. If the sample is a solid solution, then the algorithm is able to find phases of differing chemical composition belonging to the same solubility range (provided that the difference in lattice constants is not too large). One of the examples illustrates the possibility of application for electron-diffraction data.

Standardized X-ray powder diffraction data for orthorhombic LaCo0.4Fe0.6O3 prepared by calcination of a glycine-nitrate combustion-synthesized precursor are reported. Orthorhombic unit cell parameters: a = 5.4688 (2), b = 5.5100 (2), c = 7.7462 (3) Å. The reference intensity ratio, I/Icor,= 6.12.

A new titanate K2ZnTiO4 has been synthesized by solid-state reaction. This compound is isostructural with K2ZnGeO4, space group Pca21, Z=8. Unit-cell parameters were determined: a=11.3352(6) Å, b=5.6352(5) Å, c=16.0125(13) Å, and V=1022.8(3) Å3. Powder diffraction data are reported.

The temperature variation of the interplanar spacings (101), (112), and (211) of 325 mesh quartz was determined in the range 300–966 °K using X-ray powder diffractometry. The measured lattice parameters have been found to increase nonlinearly with temperature, and the dependence has been expressed by a polynomial of second degree from the least-squares fitting of the data, the results of which are presented herein. Values are given for the thermal expansion coefficients and Gruneisen parameter in the range 300 to 768 °K. In the range 768–966 °K, the expansion is zero. The derivatives dαa/dT, dαc/dT, and dαv/dT at ambient temperature are also given.