The hydration of ordinary Portland cements (OPC) was investigated with X-ray powder diffraction (XRPD) technique, mainly using synchrotron radiation. In situ experiments were performed during the first hours of hydration to study the evolution of the crystalline phases in the system. The hydration was carried out with pure water and in the presence of additives such as superplasticizers and setting accelerating agents. As soon as water is added to the cement, ettringite crystallizes. Its evolution appears to be very complex, and lattice parameters change as a function of setting time, indicating a possible chemical evolution of ettringite with time and as a function of pH. CSH (Ca-Si-hydrate) forms after a few hours from the beginning of hydration. CSH can be indirectly quantified and its evolution studied.

Transformation behaviors of the technologically important polycrystalline Ti50.75Ni47.75Fe1.50 shape memory alloy were investigated using differential scanning calorimeter (DSC) and powder diffraction techniques. DSC revealed that there are two-stage (i.e., cubic→trigonal→monoclinic) martensitic phase transformations on cooling and a one-step transformation (monoclinic→cubic) on heating. In situ structural refinement of cubic→trigonal→monoclinic on cooling was carried out using the D1A high-resolution neutron powder diffractometer at the Institut Laue-Langevin Neutrons for Science in Grenoble, France. Results showed that the phases involved during the phase transition are consistent with the differential scanning calorimeter cooling curve, and the refined crystal structure parameters obtained from Rietveld refinements with the generalized spherical harmonic description agreed reasonably well with X-ray single-crystal data. Subsequently, a combined neutron and synchrotron structural refinement for each phase was conducted because the trial refinements initially using only the synchrotron data of trigonal phase yielded a false minimum with a somewhat high goodness-of-fit χ2. Results obtained from the combined neutron and synchrotron data of the cubic, trigonal, and monoclinic phases show that the same minimum goodness-of-fit indices were always obtained.

The growth temperature dependence of the InN film’s crystalline quality is reported. InN films are grown on sapphire substrates from 570 to 650 °C with low-temperature GaN buffers by metalorganic vapor phase epitaxy (MOVPE). The X-ray rocking curves and reciprocal space mappings of the symmetric reflection (0 0 0 2) and asymmetric reflection (1 0 1 2) are measured with high resolution X-ray diffraction. The results indicate that the crystallinity is sensitive to the growth temperature for MOVPE InN. At growth temperature 580 °C, highly crystalline InN film has been obtained, for which the full-width-at-half-maxima of (0 0 0 2) and (1 0 1 2) rocking curves are 24 and 28 arcmin, respectively. The crystalline quality deteriorates drastically when the growth temperature exceeds 600 °C. Combined with the carrier concentration and mobility, the approach to improve the quality of InN film by MOVPE is discussed.

A series of Dy2Co17−xGax polycrystalline samples with x from 0 to 7 were prepared by arc melting. X-ray powder diffraction analysis indicated that these compounds have the hexagonal Th2Ni17 structure for x≤3 and the rhombohedral Th2Zn17 structure for 3.5≤x≤7. The lattice parameters a and c increase linearly with the gallium content until x=5.3. With further increasing the gallium content x up to 7, the lattice parameter c slightly decreases, whereas the lattice parameter a increases more quickly than that for 0≤x≤5.3. The unit-cell volume shows an approximately linear increase of 6.1 Å3/Ga for 0≤x≤3.0 and 10.1 Å3/Ga for 3.5≤x≤7.0, respectively. Rietveld refinement of the Dy2Co11.7Ga5.3 compound reveals that the Ga atoms occupy all the 6c, 9d, 18f, and 18h sites and preferentially occupy the 6c site. The Curie temperature and the saturation magnetization of the rhombohedral Dy2Co17−xGax compounds decrease almost linearly with increasing Ga content.

Crystal structures of (NH4)2KWO3F3 at 298 K and 113 K were solved from X-ray powder diffraction data and refined by the Rietveld technique. The compound is isostructural with elpasolite K2NaAlF6 at room temperature with space group Fm-3m, a=8.95850(5) Å, V=718.961(7) Å3, Z=4, Dx=3.363 g/cm3, and MW=364.02. The structure was refined over 18 parameters to Rwp=12.6%, Rp=10.9%, Rexp=5.03%, and RB=3.27% from 40 independent reflections. (NH4)2KWO3F3 was transformed upon cooling to a ferroelastic monoclinic phase with space group P21/n, a′=6.3072(3) Å, b′=6.3028(3) Å, c′=8.9882(3) Å, β′=90.242(2)°, V=357.30(3) Å3, Z=2, and Dx=3.383 g/cm3. The low-temperature structure at 113 K was refined over 28 parameters to Rwp=20.9%, Rp=21.3%, Rexp=12.5%, and RB=6.93% from 453 independent reflections.

The crystal structures of ruthenium oxides with the general formula Nd2−xMxRu2O7−y, where M is Cu or Ag, 0≤x≤0.25, were investigated. All compounds that were prepared exhibit the pyrochlore structure with a cubic unit cell. The compounds were characterized by X-ray powder diffraction, and single-phase structures were found for Nd2−xCuxRu2O7−y, x=0.1, 0.2, 0.25, and for Nd2−xAgxRu2O7−y, x=0.1, 0.15, 0.2. The relative metal concentrations were verified by EDS. The cell parameters were determined by advanced peak-position analysis and calibrated by a Si internal standard. Atomic positions and oxygen occupancies where refined by the Rietveld method. It was found that the cell-size modifications agree with the relations between ionic sizes.

The synthesis and X-ray powder diffraction data for the organometallic [Rh2(bim)2(cod)2]Cl2∙2H2O species are reported. Its crystal and molecular structures were determined by simulated annealing and full-profile Rietveld refinement methods. [Rh2(bim)2(cod)2]Cl2∙2H2O was found to crystallize in the orthorhombic Cmca space group. The lattice parameters were determined to be a=21.3574(6), b=10.7764(3), c=14.2795(4) Å, V=3286.5(2) Å3, for Z=4. The crystal structure was found to contain dimeric [Rh2(bim)2(cod)2]2+ cations, in which the bim ligands bridge Rh(cod) fragments with an intermetallic separation of ca. 8.90 Å. The crystal structure is completed by chloride ions and hydrogen-bonded water molecules, situated in the small cavities of the large cation substructure. The conformation of the bim ligand, lying on a crystallographic mirror plane, is rigorously Cs.

A novel synthesis method of fibrillar trimolybdates with the use of Ag2Mo3O10∙2H2O as a precursor has been used successfully to synthesize methylammonium trimolybdate, (CH3NH3)2Mo3O10∙H2O. The crystal structure of this compound was determined by X-ray powder diffraction method and refined by the Rietveld method. The compound is orthorhombic, space group Pnma (62), with a=11.241(3), b=7.585(1), and c=15.516(4) Å. The redetermined crystal structure of the precursor and the structure of the title compound are compared and discussed.

The crystal structure of recently discovered chromium (III) dimagnesium trivanadate (V) Mg2CrV3O11 was refined using the Rietveld method. The crystal system of Mg2CrV3O11 is triclinic with space group P1− (Mg1.7Zn0.3GaV3O11 type) and lattice parameters a=6.4057(1) Å, b=6.8111(1) Å, c=10.0640(2) Å, α=97.523(1)°, β=103.351(1)°, γ=101.750(1)°, and Z=2. The characteristic feature of compounds in the A2BV3O11 (A=Mg, Zn and B=Ga, Fe, Cr) family is a strong tendency to share the octahedral M(1) and M(2) sites by both divalent A and trivalent B atoms, and the bipyramidal M(3) sites occupied by divalent A ions. In the present refinement, the only constraint assuming full occupancy of the M(1), M(2), and M(3) sites leads to the following Cr/(Cr+Mg) ratios: 0.70(2) at M(1), 0.24(2) at M(2), and 0.03(2) at M(3). These occupancies are discussed and compared to those of isotypic compounds. The values of interatomic distances are found to be comparable with those reported by R. D. Shannon in 1976. Electron paramagnetic resonance has been also analyzed. Two absorption lines with g≈2.0 (type I) and g≈1.98 (type II) have been recorded in the EPR spectra, and attributed to V4+ ions and Cr3+–Cr3+ ion pairs, respectively. The exchange constant J between Cr3+ ions has been calculated.

Crystal structure of the triclinic ternary phase Cr4(Al, Si)11 was investigated by full-profile Rietveld analysis of powder diffraction data. Four hundred eighty-four reflections were refined to a final RBragg value of 5.00%. Cr4(Al, Si)11 is isostructural to Mn4Al11. Silicon atoms enter into the structure by partially replacing aluminium on the Al(1) and Al(2) sites.

Gallium iron oxide GaFeO3 and the substituted GaFeO3 with Cr and Mn, i.e., Ga(Fe0.95Me0.05)O3, and (Ga0.95Me0.05)FeO3; Me=Cr and Mn, have been synthesized and investigated by X-ray powder diffraction. The refined structural parameters of the considered samples using the Rietveld technique showed a considerable distortion in the polyhedron around different cations, which may have an effect on the piezoelectricity of the studied samples. There are also changes in the interatomic distances between different cations, which may have a direct influence on the ferromagnetic properties of the samples. Crystallite size and microstrain are anisotropic and the largest along the b axis, which may be responsible for the piezoelectricity. The correlations between all these changeable parameters will be discussed.

Four aliphatic-aromatic diols with ether linkages [4, 4′-Bis(2-hydroxyethoxy)benzophenone, 4, 4′-Bis(3-hydroxypropoxy)benzophenone, 4, 4′-Bis(6-hydroxyhexyloxy)benzophenone, 4, 4′-Bis(11-hydroxyundecyloxy)benzophenone] and two aliphatic-aromatic diols with sulfur linkages [4, 4′-Bis[(2-hydroxyethyl)thio]benzophenone, 4, 4′-Bis[(3-hydroxypropyl)thio]benzophenone] have been characterized by X-ray powder diffraction. These diols can be used for synthesis of thermoplastic nonsegmented polyurethanes. Experimental 2θ peaks positions, relative peak intensities, values of d, and Miller indices as well as unit-cell parameters are presented.

Besides statistical and graphical measures, many structural features can be used to assess the quality of a Rietveld refinement. These include the metric symmetry of the lattice (which can assist in determining the true symmetry and in identifying isostructural compounds), bond distances and angles (which should fall within normal ranges), displacement coefficients, refined stoichiometry, the absolute values of the standard uncertainties of the fractional coordinates, the hydrogen bonding pattern, the presence of approximate symmetry, the presence of unindexed peaks in the pattern, and whether the refinement converges at all. Chemical knowledge can be built into a Rietveld refinement though the use of restraints and rigid bodies. A knowledge of chemical reasonableness proved important in refining the correct structures of [Fe(H2O)6](BF4)2, (Ba1.5Sr0.5)TiO4, and (Ba1.25Sr0.75)TiO4.