The powder pattern of Rb3Ta5O14 is reported here for the first time. Single crystals of Rb3Ta5O14 of 0.1–0.2 mm in size were grown using a RbCl flux at 1100 °C. The Rb3Ta5O14 powders were synthesized at 1200 °C by firing the Rb2CO3 and Ta2O5 raw materials with starting Rb/Ta ratios ranging from 0.450 to 0.800. The products with Rb/Ta ratios between 0.550 and 0.633 contained almost pure Rb3Ta5O14 with Rb/Ta ratio of 0.600, while those with Rb/Ta ratio larger than 0.677 also contained the α form of Rb4Ta6O17 with the Rb/Ta ratio of 0.677. Past studies of the synthesis and characterization of Rb4Ta6O17 should be carefully examined in the light of possible coexistence with Rb3Ta5O14, because the former structure has not been completely solved, and thus the powder pattern is inaccurate, while the presence of the latter had not been known until the present study.

So-called alite is a solid solution of tricalcium silicate Ca3SiO5 with a few percent of impurities. It constitutes the major phase of anhydrous Portland cement. In industrial compounds, alite crystallizes into two monoclinic forms designated M1 and M3. The possibility of correlation between the crystallographic structure of the clinker and its reactivity is still an open question. The answer of such a question involves a proper quantitative analysis of the various phases—including the exact alite polymorph—of the industrial product. The rather similar structure of the two alites makes it difficult to distinguish them from their XRD patterns. This paper shows that five angular windows in the X-ray diffraction patterns can be used with synthetic alites as well as industrial compounds, to identify the nature of the actual polymorph (M1 or M3) present and the structural model to be used (with or without superstructure) in subsequent Rietveld analysis of the data.

Weight fractions of four dominant phases (C3S, C2S, C4AF and C3A) present in the NIST Reference Portland clinkers 8486, 8487 and 8488 were estimated by a series of Rietveld refinements. Calculated powder patterns were derived from the structural data for monoclinic C3S and C2S, orthorhombic C4AF and cubic C3A. X-ray diffraction data were collected in two laboratories with two diffractometers, a reflection and a transmission one. There were no significant differences between the results of the refinements based on the data sets collected on the machines with different experimental arrangements. Estimated phase compositions were compared to the reference values found by optical microscopy (MPC). Median agreement between refined and reference values within ±5% (absolute) was found only for 8488 clinker; for 8486 and C3A-rich 8487 it was within ±10% (absolute). In the majority of the refinements numerical instabilities were detected, leading to large correlations between FWHM and temperature parameters of some phases. The results obtained for C4AF were probably influenced by the presence of possible solid solutions with the structures close to that of C4AF. Weight fractions of low abundant C3A were estimated with the largest relative errors reaching in several cases ∼100%.

Two XRD specimen holders we designed for use with highly radioactive specimens are described. An injection mold was fabricated to allow inexpensive production of one of the holders. These holders are suitable for single-time use. The ease of use and disposable nature of this holder resulted in a dramatic reduction in personnel exposure and an uncontaminated diffraction unit. A second holder, based on the design of the first, is used to obtain XRD patterns from powders where preferred orientation is an issue and from clays. Both holders result in negligible background, since the specimen is essentially levitated in the X-ray beam. This is a benefit over other methods, such as collodion, that introduce significant background to the XRD pattern.

Powder X-ray diffraction (XRD) data were collected for Pr0.7Ba0.3MnO3. This sample was prepared using the conventional solid state reaction by mixing Pr6O11, Mn2O3, and BaCO3 up to 99.9% purity at 1400 °C in air for 60 h. XRD analysis using the Rietveld method was carried out and it was found that this manganite sample has orthorhombic symmetry with Pnma space group. The lattice parameters are found to be a=5.4900 Å, b=7.7578 Å, and c=5.5227 Å.

A computer program for refining anomalous scattering factors using x-ray powder diffraction data was revised on the basis of the latest version of a versatile pattern-fitting system, RIETAN-2000. The effectiveness of the resulting program was confirmed by applying it to simulated and measured powder-diffraction patterns of Mn3O4 taken at a synchrotron light source.

A new copper phosphate, CuPO4H⋅0.5H2O, was synthesized using a low temperature hydrothermal method and characterized by powder X-ray diffraction, thermogravimetric analysis, and chemical analysis. The material is monoclinic, space group P21/c, with a=10.6524(2), b=8.4730(2), c=9.2204(2), β=92.43(0), and V=831.47 Å3.

X-ray powder diffraction data for In3.85Zr2.80Sn0.35O12 are reported. The powders were prepared using a wet-chemical precipitation method. The XRD data could be fitted with a rhombohedral unit cell in space group R3 (No. 148). The Rietveld refined unit cell parameters are a=0.951 49(2) nm and c=0.889 51(2)nm in a hexagonal setting with Z=3 and Dx=6.69(1)g/cm3.

Our X-ray powder diffraction data determine that UTeO4 has an orthorhombic unit cell with parameters: a=10.115±0.003 Å, b=10.706±0.002 Å, c=7.833±0.002 Å, and v=848±0.40 (Å)3, i.e., the cell volume twice as large as that of UTeO5. IR spectral studies show that UTeO4 and UTeO5 have almost an identical molecular symmetry. In UTeO4, the effective environment of U and Te remains nearly the same as in UTeO5 and the UO2 group is noncentrosymmetric and nonlinear with little or no interaction with equatorial oxygen. Frequencies of the characteristic stretching bands of UTeO4 are (cm−1): νas (O=U=O)=945, νs (O=U=O)=880, νs (Te–O)eq=818, νas (Te–O)eq=749, νas (Te–O)ax=649, νs (Te–O)ax=561.

The X-ray powder diffraction pattern for a bridgehead heterocyclic system was determined. 2-exo-(β-pyridyl)-6-exo-phenyl-7-oxa-1-azabicyclo[2.2.1]heptane, C16H16N2O, is triclinic with refined unit cell parameters a=1.1012(2), b=1.3950(2), c=1.0074(3) nm, α=111.09(2)°, β=104.97(2)°, γ=77.38(2)°, V=1.3813(3) nm3, Z=4, and Dx=1.212 g/cm3 with space group P-1 (No. 2).

The capacity of goethite for CdII substitution has been explored in a series of synthetic samples prepared from FeIII and CdII nitrate solutions aged 21 days in alkaline media. The total metal content ([Fe]+[Cd]) was 0.071 M in all preparations. The samples have been characterized by chemical and X-ray diffraction analysis; the morphology of the solids is described. The cell parameters for all samples were obtained by the Rietveld fits to the X-ray diffraction data. Refined structures show that for samples prepared at the final molar ratio μCd≤5.50 (expressed as μCd=100×[Cd]/[Cd]+[Fe]), a (Cd, Fe)-goethite is the only crystalline product. In these samples, the unit cell parameters increased as a function of Cd concentration, indicating Cd incorporation in the structural frame. At the preparative ratio, μCd=7.03, the incorporation of Cd in the goethite structure is drastically reduced and a probable Cd-substituted hematite is formed together with the Fe,Cd-goethite.

X-ray powder diffraction data for Ba0.5Sr0.5Co0.8Fe0.2O3−δ are reported. The powder was prepared using a metal-EDTA complexing method. The XRD data could be fitted with a primitive cubic unit cell in space group Pm3m (No. 221). The Rietveld refined unit cell parameter is ac=0.398 30(3) nm with Z=1 and Dx=5.75 g/cm3.