Two carbonates Cs2Sr2(CO3)3 and Rb2Sr2(CO3)3 were synthesized by solid-state reaction at high temperatures, and their crystal structures were determined from X-ray powder diffraction data. Because of the presence of heavy atoms and heavy peak overlapping, proper restrains on light-atom groups were found essential to obtain satisfactory results. The title compounds are isostructural to an early reported compound Cs2Ba2(CO3)3 and crystallize in cubic space group I213, with unit-cell dimensions a=10.072 64(2) Å for the cesium phase and a=9.855 56(7) Å for the rubidium phase. Unlike most carbonates, the title compounds feature in mutually perpendicular CO3 atomic groups. Our results also indicate that the global instability index is a more sensitive parameter in evaluating the structure rationality over the agreement factors. Moreover, differential thermal analysis and thermogravimetric analysis measurements reveal that Cs2Sr2(CO3)3 and Rb2Sr2(CO3)3 are stable in air up to 796 and 880 °C, respectively.

A new cobalt hydroxide carbonate Co2(OH)2CO3 was successfully synthesized by a hydrothermal method. The compound is isomorphous with malachite [Cu2(OH)2CO3] and crystallizes in a monoclinic system [space group P21/a (No. 14); a=9.448(5) Å, b=12.186(9) Å, c=3.188(4) Å, β=98.593°, V=367.143(9) Å3, Z=4, and Dc=3.786(9) g/cm3]. Crystal structure of Co2(OH)2CO3 was refined by the Rietveld method with RP=4.3%, RWP=5.7%, Rexp=5.1%, RB=1.74%, and S=1.117 on the basis of the X-ray powder diffraction data. The crystal structure of Co2(OH)2CO3 obtained by the Rietveld refinement shows that all species Co2+, CO32−, and OH− ions occupy C1 site symmetry. Two crystallographically different Co2+ and OH− ions and one type CO32− ion exist in the lattice. Co(1) is coordinated to two oxygen atoms from CO32− ions and two OH− ions; Co(2) is coordinated to two oxygen atoms from CO32− ions and four OH− ions, thus forming a distorted octahedron with (4+2) coordination.

X-ray powder diffraction was used for the structural study of nonlinear optical borates K1−xNaxSr4(BO3)3 (x≤0.5). Results show that up to 50% K+ can be substituted by Na+ in orthorhombic K1−xNaxSr4(BO3)3. Isolated BO3 triangles in the Na-substituted compound constrict to adjust to a local distribution of alkali-metal atoms, which explains the large range of structural homogeneity. An expansion of the c axis in a unit cell with increasing Na substitution was found probably caused by the tilted BO3 triangles and asymmetric distortion of (K/Na)O8 polyhedra. As the ratio of ionic radii of alkaline-earth and alkali-metal cations decreases and the electronegative difference between alkaline-earth and alkali-metal cations increases, the crystal system of MM′4(BO3)3 borates changes from cubic to orthorhombic and then to monoclinic.

Samples of single-phase Sr2FeMoO6 were successfully prepared by solid-state reaction with long sintering times. The crystal structures of the Sr2FeMoO6 samples were determined from X-ray powder diffraction data using the Rietveld refinement method. The structure results obtained by the Rietveld refinements show that an increase in the total sintering time of the solid-state reaction is an effective method to obtain single Sr2FeMoO6 phase and to improve the ordering of Fe and Mo cations (or reducing antisite defects) in the double-perovskite structure. The volume of the tetragonal unit cell of Sr2FeMoO6 contracts slightly after successive sintering treatments. The averaged Fe-O and Mo-O bond lengths as well as the tilt between the FeO6 and the MoO6 octahedra decrease with increasing total sintering time. Our results suggest that the detected subtle changes in crystal structure, such as bond lengths and bond angles between the Fe and Mo cations and oxygen, in the ordered double-perovskite structure may be responsible for the large effects on previously reported transport and magnetic properties of an oxide metal.

X-ray diffraction, selected area electron diffraction, and high-resolution transmission electron microscope techniques were used to investigate the crystalline structures of one-dimensional tungsten oxide nanowires prepared by the hydrothermal method. The as-synthesized products were found to exhibit increasing crystallinity with increasing reaction time, and tungsten oxide nanowires have crystalline defects, including stacking faults, dislocations, and vacancies. The results on the crystal defects help us to obtain a better understanding of the temperature-dependent morphological evolution of the ultrathin nanowires synthesized under different thermal processes.

Polycrystalline Mn1.1Fe0.9P0.76Ge0.24 was prepared by mechanical alloying and spark plasma sintering. Neutron diffraction was used to determine the structure of the title compound, and its nuclear and magnetic structures were refined using the Rietveld method. It is found that temperature and magnetic field can induce phase transition between the paramagnetic and the ferromagnetic phases in the material, and the paramagnetic and ferromagnetic phases have very distinct crystal structures and different Ge contents.

X-ray powder diffraction data of voglibose are reported, and its crystal and molecular structures were determined by simulated annealing and rigid-body Rietveld refinement methods. Voglibose was found to be crystallized in triclinic symmetry with space group P-1. The lattice parameters were determined to be a=6.1974(6) Å, b=6.9918(5) Å, c=7.3955(9) Å, α=70.8628(3), β=103.5312(4), γ=94.3867(5)°, V=294.2(2) Å3, and ρcal=1.495 g/cm3. The crystal structure contains isolated C10H21NO7 molecular.

The structural and magnetic properties of the DyCo4−xFexGa compounds with x=0, 0.5, 1, and 1.5 have been investigated by X-ray diffraction and magnetic measurements. Powder X-ray diffraction analysis reveals that each of the DyCo4−xFexGa compounds has a hexagonal CaCu5-type structure (space group P6/mmm). The Fe solubility limit in DyCo4−xFexGa is x<1.5. The higher the value of x, the larger the unit-cell parameters a, c, V, and the 3d-sublattice moment but the smaller the 3d uniaxial anisotropy. Magnetic measurements show that the Curie temperature of DyCo4−xFexGa increases from 498 K for x=0 to 530 K for x=1.5, the compensation temperature Tcomp decreases from 286 K for x=0 to 238 K for x=1.5, and the spin-reorientation transition temperature increases from 403 K for x=0 to 530 K for x=0.5. No spin-reorientation transition was found in the samples with x=1.0 and 1.5. The saturation magnetization of DyCo4−xFexGa measured at 173 K increases but the magnetization measured at 300 K decreases with increasing Fe content x.

Transparent p-type conducting Ga-doped SnO2 thin films were prepared using reactive rf-magnetron sputtering. Good p-type conduction was directly realized without the need of postdeposition annealing. The p-type conductivity was found to be very sensitive to the growth condition and process, suggesting that the carrier behavior is strongly related to the fine microstructure of the films. The microstructures of the films were characterized using synchrotron X-ray diffraction and specular reflectivity techniques. The valence state of the Ga dopant was measured from X-ray photoelectron spectra to explain the origin of net holes presented in the films.

Mixed solvent of ethanol and water using FeSO4⋅7H2O and (NH2)2CS as precursors with polyvinylpyrrolidone as surfactant was used to synthesize cubic FeS2 (pyrite) crystals. Crystalline phase and surface morphologies of the crystals were characterized by X-ray diffraction and scanning electron microscopy, respectively. Volume ratio of solvent, reaction temperature, reaction time, and sulfur source were found to be the key parameters for the formation of pure pyrite crystals. Optimal micron-size pyrite crystals were successfully grown from a mixed solvent of ethanol and water with a volume ratio of 3:2, heated to a reaction temperature of 180 °C, and maintained for 36 h with thiourea as the sulfur source.

A 2-2-type nanostructure bilayer film of CoFe2O4/Pb(Zr0.52Ti0.48)O3 was successfully prepared on the (111)Pt/Ti/SiO2/Si substrate. The Pb(Zr0.52Ti0.48)O3 layer in the bilayer film is (111) oriented and is a mixture of tetragonal and monoclinic phases. The results from an in situ X-ray diffraction analysis of the multiferroic bilayer film under statistic magnetic field indicate that the monoclinic-tetragonal phase transition was induced by magnetostriction of the CoFe2O4 layer. A large magnetoelectric effect was obtained probably because of the different polarization directions of the tetragonal and monoclinic phases.

Materials with systematic absence of X-ray diffraction (XRD) peaks are desirable for conducting some special researches using X-ray diffraction or time-resolved X-ray scattering. This paper proposes a method for designing this kind of materials. It utilizes solid solution to reduce the structure factor of a selected reflection to zero by choosing proper components and their contents to let the reflection amplitudes from different atomic layers in a unit cell of the solid solution cancel each other completely. This method on how to select a solid solvent and how to calculate its content was illustrated using SrTiO3 as an example. A solid solution Sr1−xCaxTiO3 with a systematic absence of the (001) diffraction can be designed, and the value of x can be determined to be x=0.54 using an iteration calculation process. This result was verified by the experimental XRD pattern of a Sr0.46Ca0.54TiO3 sample.

Two-phase polycrystalline powder mixtures of YBa2Cu3O7−δ (YBCO) and xBaCuO2 (x=0, 0.05, 0.1, 0.2, and 0.3) were prepared by solid reaction. The Rietveld refinements of X-ray powder diffraction data show that BaCuO2 addition was successfully produced in superconductor YBCO and the unit-cell parameters of YBCO reach a maximum at x=0.05. The critical current density (Jc) also reaches a maximum at x=0.05 and then decreases sharply with increasing amount of BaCuO2. The change of Jc as a function of x was found to be similar to those of the unit-cell parameters. The characteristic behavior of Jc may come from the structure-parameter change of YBCO caused by BaCuO2 addition.