The crystal structure of the mineral strontiodresserite, (Sr,Ca)Al2(CO3)2(OH)4⋅H2O, from the Francon Quarry, Montreal, Quebec, Canada, has been solved from laboratory powder diffraction data using a combination of charge-flipping and simulated annealing methods. The structure is orthorhombic in space group Pnma with a=16.0990(7), b=5.6133(3), and c=9.1804(4) Å (Z=4) and the framework of the mineral is isostructural with that of dundasite. The strontium has a coordination number of 9 and the carbonate anions form a bridge between the SrO9 polyhedra and AlO6 octahedra. The water molecule lies in a channel that runs parallel to the b axis. An ordered network of hydrogen atoms could be uniquely determined from crystal-chemical principles in the channels of strontiodresserite. Ab initio density functional theory (DFT) energy minimization of the whole structure gave results in full agreement with X-ray refinement results for nonhydrogen atoms. The stability of this model (as well as that of the corresponding model of dundasite) in the proposed Pnma space group was tested by DFT optimization in space group P1 of random small distortions of this structure. This test confirms that both minerals are isostructural, including their hydrogen-bond networks.

[Zr2F8(dmso)2(H2O)2], a dehydration product of [ZrF4(dmso)(H2O)2]⋅2H2O, crystallizes in the orthorhombic symmetry [space group Cmca, a=7.8266(3) Å, b=13.5847(5) Å, c=15.6119(6) Å, and Z=4]. The structure, solved ab initio in direct space from X-ray powder diffraction data, is built up from [Zr2F8O4] bipolyhedra formed by edge sharing of [ZrF5O2] pentagonal bipyramids (condensed from isolated [ZrF4O3] pentagonal bipyramids in the precursor). Difficulties associated with a fortuitous hexagonal pseudosymmetry were surmounted. The dmso departure at 220 °C leads to an amorphous phase.

Crystal structure of Li2BaSiO4 was reinvestigated by laboratory X-ray powder diffraction. The title compound was hexagonal with space group P63cm, Z=6, unit-cell dimensions a=0.810 408(2) nm, c=1.060 829(4) nm, and V=0.603 370(3) nm3. The initial structural model was successfully derived by the direct methods and further refined by the Rietveld method, with the anisotropic atomic displacement parameters being assigned for all atoms. The reliability indices calculated from the Rietveld refinement were Rwp=6.72%, S=1.17, Rp=5.06%, RB=1.86%, and RF=0.98%. The maximum-entropy method-based pattern fitting (MPF) method was used to confirm the validity of the structural model, in which conventional structure bias caused by assuming intensity partitioning was minimized. The final reliability indices calculated from MPF were Rwp=6.74%, S=1.17, Rp=5.10%, RB=1.49%, and RF=0.69%. Atomic arrangements of the final structural model were in excellent agreement with the three-dimensional electron-density distributions determined by MPF.

The solvent-free conversion of N-carbamoyl-L-proline to hydantoin-L-proline by direct heating at 470 K is reported. A reaction mechanism is proposed based on a nucleophilic intramolecular substitution reaction involving both the lone pair of the NH2 group and the carboxylic acid group of the N-carbamoyl-L-proline. The DSC and TGA experiments show rising of the baselines of the curves prior to melting and decomposition given evidence of the onset of the thermal reaction. NMR experiments were used to identify the product of the reaction, hydantoin-L-proline, whose crystal structure was obtained from X-ray synchrotron powder diffraction data collected on the solidified melt. This compound displays a crystal packing directed by hydrogen bonds forming a layered structure pile up along the c direction.

The structure transitions and phase relationships of DyFe3−xAlx compounds have been investigated by X-ray powder diffraction. Our XRD results show that each of the compounds with x≤0.45 crystallizes in the rhombohedral PuNi3-type structure with space group R3¯m and Z=9; for the 0.8≤x<1.0 compounds, each has a hexagonal structure of the CeNi3 type with space group P63/mmc and Z=6; and each of the samples with 0.45<x<0.8 is a two-phase mixture of the PuNi3- and CeNi3-type structures. The calculated XRD intensities of the DyFe3−xAlx compounds with x=0.2, 0.33, 0.4, and 0.45 indicate that Dy occupies the 3a and 6c sites, Fe and Al distribute randomly on the 18h site, and the 3b and 6c sites are exclusively occupied by Fe, which agrees well with those of our experimental XRD patterns. The XRD intensities of the DyFe3−xAlx compounds with x=0.8 and 1.0 have also been calculated and found to agree with the experimental results with Dy on the 2c and 4f sites, Fe and Al at the 12k site, and Fe at the 2a, 2b, and 2d sites. In the two-phase region with x=0.45–0.8, the values of unit-cell parameters and phase compositions are linearly dependent on the value of x, indicating that the two phases are constituted by the same composition x with different stacking arrangements. This abnormal two-phase equilibrium is further confirmed by the structural analysis of the DyFe2.33Al0.67 (or x=0.67) sample. The samples with x=1.1 and 1.2 were also analyzed, and each found to be a mixture of more than two phases.

Shot peening was conducted on [100]- and [111]-oriented monocrystalline nickel-based superalloy samples to study the effect of crystal orientation on the distributions of the residual stress and evolution of microstructures in the deformation layers on the sample surfaces as a function of the coverage up to 400%. The XRD results show that the orientation randomizations and the values of compressive residual stress in the [111]-oriented samples are relatively higher than those in the [001]-oriented samples. Moreover, the residual-stress distribution in each sample is anisotropic, and the residual stress is maximum along the 〈110〉 direction. This phenomenon can be explained by the anisotropic properties of a single-crystal alloy and mechanism of the dislocation slip in the plastic deformation layers. Line profile analysis was also used to obtain microstructural information of the samples.

Four new compounds with general formula CdI2-2(NH2-PhX) (Ph represents phenyl radical; X represents Cl or H atoms) were obtained and characterized. Two of them, bisaniline diiodidecadmium(II) — CdI2⋅2[NH2–C6H5] {1} and bis(2-chloroaniline) diiodidecadmium(II) — CdI2⋅2[NH2–C6H4Cl] {2}, crystallize in monoclinic system, whereas another two, bis(3-chloroaniline) diiodidecadmium(II) — CdI2⋅2[NH2–C6H4Cl]{3} and bis(4-chloroaniline) diiodidecadmium(II) hemi(4-chloroanilate) — CdI2⋅2[NH2–C6H4Cl]½[NH2–C6H4Cl] {4}, crystallize in triclinic system. The investigated compounds, from chemical point of view, are similar to the so-called cisplatin—a compound used as a chemotherapy drug to treat many types of cancers. Their syntheses and results of X-ray powder diffraction studies at room and elevated temperatures are described in this paper.

X-ray powder diffraction data, unit-cell parameters, and space group for a novel platinum-based anticancer complex cis-[diiodo(1R,2R)-1,2-diaminocyclo-hexane-κN,κN′] platinum(II), Pt(C6H14N2)I2, are presented [a=14.048(4) Å, b=7.588(3) Å, c=11.502(4) Å, β=98.446(5)°, space group C2, cell volume=1212.80 Å3, and Z=4]. All measured lines were indexed and are consistent with the C2 space group. No detectable impurities were observed.

A new nickel zinc chromate with the composition of (NH4OH)3/2NiZn2Cr2O9⋅2H2O was synthesized by hydrothermal method. The compound was characterized by XRD, TGA, and XRF. X-ray powder diffraction data show that the crystal system of the title compound is hexagonal with space group R-3m, z=3, and unit-cell parameters: a=5.9794 and c=21.4875 Å.

A useful procedure is described to rapidly obtain Bragg-reflection intensities from the FULLPROF suite, and the Bragg intensities can then be input into the GEST and the PECKCRYST programs for crystal-structure determination of small molecules. An example on using the new procedure for the structure determination from powder diffraction determination of hydrochlorothiazide (C7H8ClN3O4S2) is presented, and the powder-structure results obtained by the PECKCRYST program are in good agreement with previously reported single-crystal results.