There are 39 CRYSTMET® entries in the hexagonal space group P-3m1 (164) reporting both distinct pure phase compounds and atomic coordinates. Having the same Wyckoff positions in the same space group as the C6 structure type, all are isopointal with it. The range of observed c/a values extends from about 0.65 to 1.83. Three types are distinguished: Layered materials with CdI2 type, the CeCd2 type which is a slight distortion of the hexagonal AlB2 type, and the intermediate EuGe2 type made of the materials AuTe2, BaSi2, EuGe2, and SrGe2. Ab initio modeling of the 26 entries with CdI2 and EuGe2 type and atomic coordinates reproduces convincingly both their c/a axial ratios and z coordinates. For CoO2 and SiTe2, both c/a and z deviate to a degree from the reported values, indicating that those materials should be reexamined for superstructures, stoichiometry, etc. Ab initio modeling of the 11 cell-and-type entries with CdI2 type and no coordinates in CRYSTMET reproduced convincingly their reported axial ratios. The X-ray cell data and the ab initioz coordinates were then used in the production of reliable calculated powder patterns for CoTe2, CrSe2, HfS2, HfSe2, HfTe2, NbTe2, SnSe2, VS2, VTe2, ZrS2, and ZrTe2. All 11 patterns have been inserted in the intense diffraction line search system of CRYSTMET operated under the Materials Toolkit. Comparison of calculated patterns for SnSe2 and ZrTe2 with experimental entries in the PDF exposes the complementarity of calculated and experimental powder patterns and suggests that JCPDS pattern #15-223 should be reinterpreted in terms of the CdI2 structure type. The CeCd2⇔AlB2 type transformation is modeled and discussed on YCd2 using both ab initio methods and a hard-sphere model. For z<0.45, the ab initio solution is identical with that from the hard-sphere model while a quantum regime is predicted in the small region 0.45<z<0.467 beyond which YCd2 abruptly transforms to the AlB2 type. In spite of the new understanding gained, this modeling fell slightly short of allowing calculation of z values and powder patterns for the materials CaHg2, DyHg2, ErCd2, GdHg2, HoCd2, HoHg2, LuCd2, NdCd2, SmHg2, TbCd2, and TbHg2 with no coordinates in CRYSTMET.

A recently developed Rigaku parallel-beam X-ray diffraction system equipped with a parabolic graded-multilayer mirror in the incident beam and a parallel-slits analyzer in the diffracted beam was used for precision high-temperature diffraction studies. The lattice parameters a and c of α-Al2O3 at room temperature and up to 1473 K were determined with precision in the range of 0.6–7.3×10−5. The thermal expansion coefficients for a and c agreed with literature values to better than 3%. The system was used successfully also to determine the Debye characteristic temperature of Si and to study structural phase transition of LaCoO3 from rhombohedral at room temperature to cubic at 1700 K.

The existence of glass or amorphous component in Portland cement clinker has been questioned for a long time. However, besides the crystalline phases, there are reports in the literature of noncrystalline material in cement clinker, which is considered to be the residue of the melt that has failed to crystallize. Absolute phase abundances were determined in this study by Rietveld refinements with laboratory X-ray data, using both internal and external phase composition standards. The results clearly demonstrate the existence of an amorphous component in Portland cement clinker. The presence of an amorphous component was also apparent from diffraction data for clinker from which the silicate phases had been chemically removed, using both laboratory X-ray and synchrotron radiation patterns.

Samples of amorphous Se, SSe40, SSe30, and SSe20 were synthesized and were then crystallized by annealing at 373 K for 5, 20, and 120 mins. The results showed that the changes in the structural and microstructural parameters for samples SSe40, and SSe30 are different from those of sample SSe20. These discrepancies are being discussed in terms of the peak shifts in both the amorphous and crystalline state, the percentage of sulfur compositional variations, and finally in terms of the probable site occupancy of the sulfur atoms in the selenium structure.

The phases developed upon annealing of ZnSe, CdSe, and CdS semiconductors in air are investigated applying X-ray qualitative and quantitative phase analysis. The compositions of the thermally grown oxides over the 373–773 K temperature range are found to be ZnO and ZnSeO3 for ZnSe, CdSeO3 for CdSe and CdSO4 and Cd3O2SO4 for CdS. The percentage phase abundance of each phase is determined at each temperature applying a standardless method. At all temperatures, the oxides are predominantly ZnO with about 10% ZnSeO3 at 773 K in case of ZnSe and CdSO4 with about 9% Cd3O2SO4 at 773 K in case of CdS. The rate of oxidation with temperature is found to be nonlinear for the three chalcogenides. CdS is found to be more resistible for oxidation than CdSe and ZnSe.

A simple ashing procedure for a mixture containing kaolinite and chrysotile is described that converts kaolinite to amorphous metakaolinite while retaining the diffraction intensity of chrysotile. This ashing procedure removes the X-ray diffraction (XRD) pattern overlap between kaolinite and chrysotile that can interfere with the analysis of even high concentrations of chrysotile. Samples are ashed at 460 °C in a muffle furnace for 40 h to completely convert kaolinite to metakaolinite. The complete conversion of 1 g of kaolinite under these conditions was determined for two standard kaolinite samples from Georgia, KGa-1 and KGa-2. Two of the most common types of commercial chrysotile, long-fiber Canadian and short-fiber Californian chrysotile, are demonstrated to retain diffraction intensity after ashing at 460 °C. Both chrysotile samples have the same integrated intensity for the (002) reflection prior to ashing, although the peak breadths for the two samples are quite different. Ashing at 480 and 500 °C reduces the diffraction intensities of both chrysotile samples by 15%, and broadens the peaks by approximately 3%. Using the prescribed ashing procedure and x-ray diffraction with an internal corundum standard, two kaolinite-bearing building materials containing chrysotile near 0.01 mass fraction were analyzed. The ashing procedure has additional advantages in reducing some samples to powders and removing volatile components, thereby eliminating some sample preparation procedures and concentrating any chrysotile present in the sample. The removal of volatile components improves the sensitivity of XRD analysis to concentrations below 0.01 mass fraction chrysotile.

The structure of BaSrR4O8 (where R=La, Nd, Sm, Gd, Eu, Dy, Ho, Y, Er, Tm, Yb, and Lu) has been investigated, and the X-ray reference patterns of these compounds have been prepared using the Rietveld refinement technique. BaSrR2O4 are isostructural to BaR2O4, which have the CaFe2O4 structure type (orthorhombic, Pnam). The cell parameters of these compounds (R=Lu to La) range from 10.125 04(10) to 10.5501(8) Å for a, 3.362 49(3) to 3.692 04(24) Å for b, 11.846 91(13) to 12.5663(9) Å for c, and 403.33 to 489.47 Å3 for V, respectively. There is a linear relationship between V and the Shannon ionic radius of R. Unlike the BaR2O4 compositions (R=Tm, Lu, and Yb), which produced a mixture of Ba3R4O9 and unreacted lanthanide oxides, single-phase BaSrTm4O8, BaSrLu4O8, and BaSrYb4O8 were successfully prepared.

A new variety of ammonium lanthanum sulfate, β-(NH4)La(SO4)2, was synthesized hydrothermally. The crystal structure was solved ab initio from powder diffraction data collected using a conventional X-ray source. The powder diffraction pattern was indexed by the successive dichotomy method: The symmetry is monoclinic, space group Pn, cell dimensions a=6.9365(4) Å, b=9.0055(5) Å, c=5.4541(4) Å, β=90.672(8)°, V=340.68(3) Å3 and Z=2 [M20=65, F30=124(0.0071,34)]. Direct methods were used for structure solution, and refinement of the atomic coordinates was carried out by the Rietveld method (RF=0.061, Rwp=0.099). The structure contains anionic layers built from lanthanum atoms ninefold coordinated to monodentate and bidentate sulfate oxygen atoms. Ammonium groups, which provide hydrogen bonds, are located between the layers. The crystal structure contrasts with that of the α phase, which is less dense by a factor of 4.4%.

Rietveld refinement using synchrotron powder X-ray diffraction data revealed that the crystal structure of synthetic Na-birnessite is triclinic (C1), not monoclinic as was previously reported. The Mn–O octahedra have elongated axial bonds, consistent with Jahn–Teller distortion resulting from partial occupancy by Mn3+. Mean Mn–O distances indicate that Mn sites are ∼2/3 Mn4+ and ∼1/3 Mn3+. The interlayer Na cations and H2O molecules occupy a split site that shows evidence of considerable disorder.

The atomic displacement parameters of individual ions in SrO have been determined from the Rietveld analysis of high-resolution powder neutron diffraction data. As the neutron velocity is smaller than the sound velocity in SrO, the intensity data was not corrected for the effect of thermal diffuse scattering. The room temperature value of overall isotropic thermal displacement parameters was B=0.57(2) Å2; which corresponds to Debye temperature, Θ of 242(4) K. The results are compared with experimental and theoretical estimates.

The compound Ba4Eu3F17 was prepared by heating pre-dried BaF2 and EuF3 (4:3) at 800 °C for 8 h in static vacuum. The colorless polycrystalline product obtained was characterized by Rietveld refinement of the observed powder diffraction data with a starting model of Ba4Y3F17. The title compound Ba4Eu3F17 crystallizes in rhombohedral lattice with lattice parameters, a=11.1787(4) and c=20.5789(10) Å, Z=3 (Space group R 3, No. 148). The Ba4Eu3F17 structure can be described as an ordered anion-rich fluorite type structure with the formation of Eu6F37 clusters. There are two crystallographically distinct Ba (CN=10, 11) and one distinct Eu (CN=8). The typical Ba(1)–F, Ba(2)–F, and Eu–F bond lengths range from 2.56 to 2.83 Å, 2.54 to 3.25 Å, and 2.24 to 2.49 Å, respectively. The salient feature of the structure is that the EuF8 polyhedra share their corner to form a cubo-octahedron of fluoride ions. The cubic BaF8 polyhedra of BaF2 are modified to Ba(1)–F10 and Ba(2)–F11 polyhedra in this structure. The cubo-octahedron encloses extra fluorine F(8) inside it.

Magnesiumchromite, MgCr2O4, undergoes a structural transition from a cubic spinel structure [space group Fd3m, a=8.32768(4) Å at 16 K] into a tetragonal distorted structure [space group I41/amd, a=5.89199(5) Å, c=8.31677(8) Å at 10 K], isotypic with Hausmannite, Mn3O4. This phase transition is translationengleich and takes place very close or at the antiferromagnetic ordering temperature.

Synthetic analogues of the minerals natisite and for the first time of paranatisite were prepared hydrothermally at 200 °C in the system Na2O–TiO2–SiO2–H2O. The obtained powder x-ray diffraction (XRD) patterns were interpreted by the Powder Data Interpretation (PDI) software package. As a result improved indexing and unit cell parameters refinements of these two phases were achieved. Synthetic natisite is tetragonal, space group—P4/nmm, a=0.649 67(8) nm, c=0.508 45(11) nm, V=0.214 50(10) nm3, Z=2, Dcal=3.13 g.cm−1, F30=37.48, M20=52.79. Synthetic paranatisite is orthorhombic, space group—Pmma, a=0.983 86(29) nm, b=0.919 23(19) nm, c=0.481 84(12) nm, V=0.435 78(19) nm3, Z=1, Dcal=3.01 g.cm−1, F30=16.42, M20=29.21.

A nonlinear optical material, N-(p-methoxy benzoyl)-N′-(p-methyl phenyl) thiourea (C16H16N2O2S), has been characterized by X-ray powder diffraction. Experimental values of 2θ corrected for systematic errors, relative peak intensities, values of d, and the Miller indices of 94 observed reflections with 2θ up to 66° are reported. The powder diffraction data and the figure-of-merit are reported. The least-squares refined unit cell parameters are a=25.3291(3) Å, b=11.9478(1) Å, c=10.1407(4) Å, β=103.10(2)°, V=2988.97(6) Å3, Z=8, Dx=1.335(0) g/cm3, with space group P21(4).

A nonlinear optical material, N-(p-methoxy benzoyl)-N′(o-methyl phenyl) thiourea (C16H16N2O2S), has been characterized by X-ray powder diffraction. Experimental values of 2θ corrected for systematic errors, relative peak intensities, values of d, and the Miller indices of 90 observed reflections with 2θ up to 88° are reported. The powder diffraction data have been evaluated, and the figures-of-merit are reported. The least-squares refined unit cell parameters are a=26.7079(3) Å, b=6.7995(9) Å, c=19.2845(1) Å, β=121.39(4), V=2989.42(3) Å3, Z=8, Dx=1.334(8) g/cm3, space group P2(3).

The current JCPDS powder pattern for the racemic compound fenoprofen calcium dihydrate (card No. 44-1790) is unindexed. Previously we reported the single crystal data, determined at −100 °C, for this material (Zhu et al., 2001). Using 2θ values obtained from a powder pattern spiked with internal standards, we indexed the room temperature powder pattern. The resulting unit cell values for the monoclinic P21/n cell are a=19.018 Å, b=7.738 Å, c=19.472 Å, β=91.66°.

X-ray powder data originally published for the zeolite mineral goosecreekite are of poor quality. The new data reported here for material from Norway are compared with powder data calculated from the published structure. The cell is monoclinic (space group P21, Z=2), a=7.422(2) Å, b=17.414(4) Å, c=7.288(2) Å, β=105.43(3)°, V=907.9(3) Å3. F30=32.75(0.023,40).