Details of the quantitative techniques successfully applied to artificial rock mixtures distributed for the third Clay Minerals Society Reynolds Cup (RC) contest are presented. Participants each received three samples, two containing 17 minerals each and a third containing ten minerals. The true composition of the samples was unknown to all participants during the contest period. The results submitted were ranked by summing the deviations from the actual compositions (bias). The top three finishers used mainly X-ray diffraction (XRD) for identification and quantification. The winner obtained an average bias of 11.3% per sample by using an internal standard and modified single-line reference intensity ratio (RIR) method based on pure mineral standards. Full-pattern fitting by genetic algorithm was used to measure the integrated intensity of the diagnostic single-line reflections chosen for quantification. Elemental-composition optimization was used separately to constrain phase concentrations that were uncertain because the reference mineral standards were lacking or not ideal. Cation exchange capacity, oriented-sample XRD analysis, and thermogravimetric analysis were also used as supplementary techniques. The second-place finisher obtained an average bias of 13.9%, also by using an RIR method, but without an added internal standard and with intensity measured by whole-pattern fitting. The third-place finisher, who obtained an average bias of 15.3%, used the Rietveld method for quantification and identification of minor phases (using difference plots). This participant also used scanning electron microscopy (with X-ray microanalysis) to identify minor components and verify the composition of structures used in Rietveld analysis. As in the previous contests, successful quantification appears to be more dependent on analyst experience than on the analytical technique or software used.

The structure of prehnite Ca2Al(AlSi3O10)(OH)2, including H positions, has been determined by a combination of single-crystal X-ray diffraction and neutron powder diffraction on four natural samples. The symmetry of the average structure with Al/Si disordered at the T2 siteis Pncm. However, for four of the crystals studied, numerous violations of the n- and c-glide reflection conditions indicate lower symmetry corresponding to space groups P2cm and P2/n and Al-Si ordered structures, possibly as domains of different symmetries and ordering within a single crystal. Time-of-flight neutron powder diffraction was carried out on a sample from Mali at 293 K and 2 K. The structure was refined in space group Pncm by Rietveld analysis. Although it was not possible to locate the missing H using the 293 K neutron data, these data were used to refine the H position located approximately by single-crystal XRD and to refine Uiso. For the 2 K neutron powder diffraction data, H was located directly by difference-Fourier synthesis and its refined position found to be in close agreement with that obtained by the combined XRD/neutron 293 K dataset.

A comparison of Rietveld refinement results for a bauxite-bearing regolith and its clayey cover in the Amazon region was made with stoichiometric calculations from chemical analysis and partly from thermogravimetric results. For this investigation a profile in the bauxite-bearing regolith occurrence in the ALCOA bauxite mine at Juruti, Brazil was studied. The different minerals, their compositions and their low crystallinity in the different horizons were investigated and the contents determined. It is evident that some minerals show several generations and some chemical composition changes that must be included in the Rietveld refinement. Al-rich hematites and goethites are common along the bauxite profile. Amorphous contents were determined with rutile added as an internal standard and shown to have gibbsite- or kaolinite-like composition. The minerals could be quantified in the different horizons and the difficulties were mainly related to variable crystalline aspects of the phases. Rietveld refinement can be a powerful tool in bauxite prospecting, quality control and during mining and beneficiation of ore minerals using the adapted refinement strategies.

Zn-exchanged natural clinoptilolite was studied by powder X-ray diffraction and positron annihilation lifetime spectroscopy. The original clinoptilolite tuff was subjected to size fractionation by sedimentation and dissolution of cristobalite (opal-C). After Zn2+-exchange the purified clinoptilolite sample contained 2.2 Zn2+ ions per unit cell. Structural details obtained by Rietveld refinement showed that the Zn2+ cations are located in three sites (Zn1, Zn2 and Zn3) in the channels of the clinoptilolite. Site Zn1 is located in the centre of channel-A (Mg2+-M4 site). Site Zn2 is in channel-B, next to the calcium M2 position. A new Zn3 site is located in channel-A, in imminent proximity to Zn1. Positron Annihilation Lifetime Spectroscopy (PALS) was employed to assess the Zn exchange. As the cation content influences the free volume of the channels, the ionexchange process can be monitored by PALS. The results suggest the existence of two sizes of cavities, in accordance with the structural refinement.

In this study, the application of (an)isotropic size determination using a recently proposed model for the double-Voigt approach is demonstrated and validated against line profile simulations using the Whole Powder Pattern Modelling approach. The fitting of simulated line profiles demonstrates that the attained crystallite sizes and morphologies are in very reasonable agreement with the simulated values and thus demonstrate that even in routine application scenarios credible size and morphology information can be obtained using the double-Voigt approximation. The aim of this contribution is to provide a comprehensive introduction to the problem, address the practical application of the developed model, and discuss the accuracy of the double-Voigt approach and derived size parameters. Mathematical formulations for the visualization of modeled morphologies, supporting the application of the recently developed macros, are additionally provided.

Two different crystalline structures corresponding to a zinc adipate and a zinc succinate were determined combining: X-ray powder and single-crystal diffraction, infrared spectroscopy, thermal analysis, and true densities experiments. The zinc succinate crystal structure was determined by single-crystal X-ray diffraction. This compound crystallizes in the orthorhombic space-group Cccm with unit-cell parameters a = 4.792(1) Å, b = 21.204(6) Å, c = 6.691(2) Å, V = 679.8(3) Å3, and Z = 8. Zinc adipate crystal structure was refined from the laboratory X-ray powder diffraction data by the Rietveld method. It crystallizes in the monoclinic space group P2/c with unit-cell parameters, a = 16.2037(17)Å, b = 4.7810(2)Å, c = 9.2692(6)Å, β = 90.329(3)°, V = 718.07(9) Å3, and Z = 4. The thermal expansion of it was estimated in 5.40 × 10−5 K−1. This contribution is a step on the way to systematize the regularities in the coordination diversity between linear dicarboxylates and transition metal–inorganic buildings units of metal–organic frameworks.

The crystal structure of levalbuterol hydrochloride polymorph A has been solved and refined using synchrotron X-ray powder diffraction data, and optimized using density functional techniques. Levalbuterol hydrochloride polymorph A crystallizes in space group P21 (#4) with a = 8.499 352(15), b = 6.511 726(13), c = 13.182 256(25) Å, β = 102.1157(2)°, V = 713.327(2) Å3, and Z = 2. The most prominent feature of the structure is the two different sorts of hydrogen bonds. Both of the ammonium hydrogens and O17–H40 act as donors to Cl18. The graph sets are C1,2(4) and C1,2(7). The result is a zig-zag chain parallel to the b-axis. The two hydroxy groups at the phenyl end of the molecule form another set of chains, both with graph set C1,1(6), also resulting in a chain parallel to the b-axis. The bulk of the molecule connects these chains in the (101) plane to form a three-dimensional network. The powder pattern is included in the Powder Diffraction File™ as entry 00-064-1494.

The crystal structure of rilpivirine has been solved and refined using synchrotron X-ray powder diffraction data, and optimized using density functional techniques. Rilpivirine crystallizes in space group P21/c (#14) with a = 8.39049(3), b = 13.89687(4), c = 16.03960(6) Å, β = 90.9344(3)°, V = 1869.995(11) Å3, and Z = 4. The most prominent features of the structure are N–H···N hydrogen bonds. These form a R2,2(8) pattern which, along with C1,1(12) and longer chains, yield a three-dimensional hydrogen bond network. The powder pattern has been submitted to International Centre for Diffraction Data, ICDD, for inclusion in future releases of the Powder Diffraction File™.

HighScore with the Plus option (HighScore Plus) is the commercial powder diffraction analysis software from PANalytical. It has been in constant development over the last 13 years and has evolved into a very complete and mature product. In this paper, we present a brief overview of the suite focusing on the latest additions and its user-friendliness. The introduction briefly touches some basic ideas behind HighScore and the Plus option.

The crystal structure of folic acid dihydrate has been solved and refined using synchrotron X-ray powder diffraction data, and optimized using density functional techniques. Folic acid dihydrate crystallizes in space group P212121 (#19) with a = 7.275 78(3), b = 8.632 17(4), c = 32.417 19(22) Å, V = 2035.985(18) Å3, and Z = 4. The structure is dominated by a three-dimensional network of hydrogen bonds. The dicarboxylic acid side chain occurs in a bent conformation, helping explain the ability of folate derivatives to coordinate metal cations. The powder pattern has been submitted to ICDD for inclusion in future releases of the Powder Diffraction File™.

Commercial dutasteride crystallizes in the orthorhombic space group P212121 (#19), with a = 7.587 44(3), b = 9.960 80(5), c = 33.500 42(12) Å, V = 2531.862(17) Å3, and Z = 4. The structure was solved and refined using synchrotron powder diffraction data, Rietveld, and density functional techniques. The most prominent feature of the structure is a zigzag chain of strong N–H···O = C hydrogen bonds along the a-axis. The powder pattern has been submitted to ICDD for inclusion in future releases of the Powder Diffraction File™.

Commercial atomoxetine hydrochloride crystallizes in the orthorhombic space group P212121 (#19), with a = 7.362 554(12), b = 13.340 168(27), c = 16.701 887(33) Å, V = 1640.421(5) Å3, and Z = 4. The structure was solved and refined using synchrotron powder diffraction data, and Rietveld and density functional techniques. The most prominent feature of the structure is zigzag chains of N–H···Cl hydrogen bonds along the a-axis. The powder pattern has been submitted to the ICDD for inclusion in future releases of the Powder Diffraction File™.

The application of the Rietveld method to quantify mineral components of bauxite and lateritic samples was carried out in order to determine the ability of the method to obtain accurate mineralogical abundances for these materials. The method was initially applied to synthetic mixtures using both Cu and Co Kα radiations, and it was shown that Rietveld-derived data compared favourably with the weighed compositions. Application to two types of natural bauxite resulted in a high correlation between Rietveld predicted values and those calculated by proportioning peak intensities with chemical assays. The use of the whole pattern rather than selected peak intensities gives greater accuracy, confirmed by a strong correlation between derived oxide concentrations from XRF assays. Accuracy and precision were improved by the determination of isomorphous substitution of aluminum in goethite and hematite by refinement of unit cell dimensions. Importantly, the ability of the Rietveld program to successfully model several goethites with different levels of isomorphous substitution improved the correlation between predicted and calculated values. In addition, crystallinity and crystallite size that influence the reactivity of the mineral components can be derived from refined peak profiles.

The crystal structures of some nickel hexacyanoferrates (II, III), including mixed compositions containing Na+, K+ and Cs+, were resolved and refined from XRD powder patterns. Data from infrared, Mössbauer and adsorption techniques provided complementary structural information. The crystal structures of Ni3[Fe(CN)6]2⋅16H2O and NiCs2[Fe(CN)6] were refined in space group Fm3m. NiNa2[Fe(CN)6]⋅2H2O and NiK2[Fe(CN)6]⋅2H2O were found to be orthorhombic (space group Pmn21). This structure (Pmn21) results from a distortion around the alkali ion, which appears as a monohydrated interstitial species. On ionic exchange in an aqueous solution containing Cs+, the orthorhombic distortion disappears and the cubic cell is obtained. Cs+ is a large cation and space is not available for interstitial water molecules. This orthorhombic model is also supported by the Mössbauer spectra of the ferrous analogs, FeK2[Fe(CN)6]⋅xH2O and Fe[Pt(CN)6]. © 2004 International Centre for Diffraction Data.

Results of crystal structure refinements and phase quantification for samples of Co-doped lanthanum chromites with nominal composition LaCr1−xCoxO3, for x=0.00, 0.10, 0.20, and 0.30, prepared by combustion synthesis are presented. The resulting powders were characterized by scanning electron microscopy and X-ray diffraction (XRD). The XRD patterns were obtained with Cu Kα radiation for non-doped lanthanum chromite sample and additionally with Cr Kα radiation for Co-doped lanthanum chromites samples, in order to enhance the signal from scattering. Rietveld analysis of XRD data showed that the studied samples presented the lanthanum chromite with an orthorhombic structure (Pnma), except for the composition with x=0.30, in which the space group was found to be R3c.

Rietveld refinement of LixCoO2-type cathodes (where x=0.59–1.00) has been demonstrated to yield quantitative information about the Li occupancy with an error of about ∼10%. With careful X-ray diffraction (XRD) data collection, refinement, and proper calibration, accurate values can be obtained. Rietveld refinement tends to under-predict the Li occupancy values in charged (de-lithiated) cathodes as compared to ICP measurements. A Li-gradient model that assumes a decreasing concentration of Li from the particle core to its surface is discussed to explain this observation. The observed lattice parameters for the fully lithiated LiCoO2 standard phase (R-3m symmetry) were a=2.8155(1) Å, c=14.052(1) Å. The error convention used in this paper is 3σ of standard deviations obtained from Rietveld refinement output.

Mn2+ and Cd2+ form a family of isostructural hexacyanoferrates(II,III). Their crystal structures, including those of mixed compositions containing K+ and Cs+ as charge balance cations, were resolved and refined from XRD powder patterns. The crystal structures of M3[Fe(CN)6]2⋅xH2O and MCs2[Fe(CN)6] (where M=Mn, Cd) were refined in the space group Fm3m. The mixed salts, MK2[Fe(CN)6]⋅2H2O, were found to be orthorhombic (space group Pmn21). The orthorhombic structure results from a local distortion due to monohydrated potassium ions located in interstitial sites. On ionic exchange in an aqueous solution containing Cs+, the orthorhombic distortion disappears and the cubic cell is obtained. Cs+ is a large ion, which practically fills the available interstitial voids stabilizing the cubic structure. In solutions of K+ and Cs+ the single salts, M2[Fe(CN)6]⋅8H2O (monoclinic P21/n) also transform, in this case liberating M2+ ions and forming the corresponding mixed salts. An analogous but slow structural transformation was also observed in the anhydrous forms of these single salts. These structural transformations could be relevant to the use of these compounds as ion exchangers and particularly for the sorption of 137Cs+ from radioactive waste solutions. The XRD data were complemented with structural information from infrared (IR), Mössbauer and water vapor adsorption techniques. © 2004 International Centre for Diffraction Data.

Ba(3−x)Srx(PO4)2 orthophosphates (0≤x≤3) have been prepared by solid state reaction. The final temperature was 1000°C. The X-ray diffraction analyses show the existence of a continuous solid solution. Ba(3−x)Srx(PO4)2 orthophosphates (0≤x≤3) crystallize in the hexagonal system with the space group R3m. Their structure is based on a three-dimensional framework constructed of infinite layers of Ba1/Sr1O12 linked and parallel to infinite layers of Ba2/Sr2O10 polyhedra and PO4 tetrahedra.

The anhydrous acid strontium oxalate Sr(HC2O4)⋅½(C2O4) was obtained by thermal decomposition of the hydrated acid strontium oxalate Sr(HC2O4)⋅½(C2O4)⋅H2O. This non-hygroscopic compound crystallizes in the space group P 21/c (No. 14) with unit cell parameters: a=0.796 61(7) nm, b=0.9205(1) nm, c=0.731 98(8) nm, and β=102.104(8)°. Final refinement of the X-ray powder data yielded RB=3.2% and Rwp=11.1% (background-corrected data). In this structure, Sr is eight-fold coordinated by O. These polyhedra are connected together by edge-sharing to form two-dimensional (2D) layers along the bc-plane, which means that there is an increased dimensionality from 1D to 2D with decreasing water content of the acid oxalates.

GSAS instrument parameters are tabulated for a variety of laboratory and synchrotron diffractometers to give users an idea of the typical ranges of profile parameters when they generate their own instrument parameter files. For modern high-resolution laboratory diffractometers, the parameters fall in the ranges 0<U<3, V=0, 0<W<4, 1<X<3, 0<Y<3, 1<asym<3, and 0<S/L<0.03. For synchrotron diffractometers, the parameters fall in the ranges 0<U<1.2, −1<V<0, 0<W<1, 0<X<1, 0<Y<1, 0<asym<0.5, 0<S/L<0.001, and 0<H/L<0.007. FULLPROF equivalents are also reported. The factors which are convoluted together to generate the instrument profile are described.