Methods using X-ray fluorescence have been developed to identify cometary material captured in aerogel during the NASA Stardust mission to Comet 81P/Wild 2. These analytical methods are necessitated by the levels of trace contaminants present in the aerogel. The cometary material disaggregates during deceleration in the aerogel, so fluorescence mapping of the entire track (which can be several millimeters long) is necessary. Distinguishing those pixels which have cometary material and aerogel from those which have only cometary material can be very challenging. We have chosen a “dual threshold” method, with some pixels clearly having only aerogel (plus contaminants) and other pixels clearly having cometary and aerogel material. Between these two threshold levels is a set of pixels which cannot be easily ascribed to one or the other. By leaving these pixels out of the analysis, the estimate of cometary material is improved.

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.

New XRD total pattern fitting software MSTRUCT was used to study the microstructure of magnetron-deposited TiO2 thin films. MSTRUCT is an extension of the FOX program for structure determination from powder diffraction data. MSTRUCT makes corrections for refraction and absorption, residual stress, and preferred orientation that are necessary for thin-film analysis using the parallel-beam geometry and an asymmetric detector scan with small angles of incidence. The program also corrects for crystallite size broadening in terms of log-normal distribution, two models of strain (phenomenological and dislocation models), as well as the influence of stacking faults in the most common cubic and hexagonal structures. The microstructure results obtained by this study show that during crystallization of the amorphous TiO2 films, tensile stresses were generated resulting in anisotropic shifts of diffraction peaks. This was confirmed by in situ crystallization and direct stress measurements. The consideration of the stress effect in terms of the weighted Reuss-Voigt model improved the fits significantly. The stresses were found to depend systematically on the TiO2 film thickness, and their values determined by total pattern fitting agree well with the values measured directly by XRD stress analysis.

Reported results for four new cubic compounds NdMMgMn2O6 (M=Li, Na, K, Cs) are questionable and cast doubt on the existence of such compounds. The lattice constants and relative intensities are essentially the same regardless of the nature of M; the X-ray diffraction patterns may be indexed with the lattice constants divided by √8, which result in much better figures of merit and a=0.3861 to 0.3883 nm, close to the subcell parameter of non-stoichiometric pseudocubic NdMnO3.

A novel hexaborate, Na2ZnB6O11, has been successfully synthesized by solid-state reaction and ab initio crystal-structure analysis has been completed using powder X-ray diffraction data. The compound crystallizes in the monoclinic space group Cc with lattice parameters a=10.7329(2) Å b=7.4080(3) Å, c=11.4822(2) Å, and β=112.16(2)°. The number of chemical formula per unit cell is Z=4 and the calculated density is 2.768(3) g/cm3. It represents a new structure type in which double-bridge-ring [B6O11]4− groups were found as fundamental building units. The infrared spectrum confirms the presence of both [BO3]3− groups and [BO4]5− groups.

The room temperature powder pattern of lapatinib ditosylate monohydrate (active ingredient in Tykerb used to treat refractory breast cancer) was indexed and the cell from the single crystal X-ray diffraction structure was refined using the experimental capillary data. Unit-cell parameters for the orthorhombic compound with space group Pbca refined from powder diffraction data are a=9.6850±0.0009 Å, b=29.364±0.003 Å, and c=30.733±0.003 Å, α=β=γ=90°, z=8, V=8740.1 Å3. Values of 2θ, d, I, and Miller indices are reported.

A new classification of opals through X-ray powder diffraction (XRPD) methodology, by analysing 75 new samples of opal came from different worldwide areas, is introduced. A brief historical summary of the application of XRPD analysis on opals and the most important XRPD results reported in literature were compared with the newly obtained XRPD data. A simple method for the classification of opals on the basis of their degrees of structural order-disorder calculated from the diffraction data is proposed. In addition, a clear boundary, which has not been previously described by others in literature, related to the presence (or absence) of two-peak characteristic of the cristobalite phase is identified. This boundary allows for a discrimination of opals C from CT.

Polycrystalline BaTi1−x(Zn1/3Nb2/3)xO3 (x=0.025 and 0.9) compounds were synthesized successfully and studied by XRD and dielectric measurements. The effects of the Ti/(Zn,Nb) ratio on the structure and dielectric properties of the compounds were investigated. XRD results indicated that the crystal structure of the x=0.09 compound is cubic perovskite with space group Pm3m and a=4.0095(4) Å. For the x=0.09 compound, a splitting of the (200) peak was observed near 40.2°, indicating that the crystal structure changed from cubic to tetragonal, with space group P4mm, a=4.026(4) Å, and c=4.0091(4) Å. Rietveld refinement of the crystal structures led to final confidence factors Rp=0.0353 and Rp=0.0349 for x=0.025 and 0.9, respectively. Dielectric measurements showed a relaxor behavior present in BaTi0.1(Zn1/3Nb2/3)0.9.

A new way of incorporating powder diffraction data into a cost function to predict the crystalline structure of inorganic solids is proposed. This approach was applied to the following series of compounds: cubic SrTiO3, tetragonal NaNbO3, TiO2 (anatase), tetragonal CaTiO3, and hexagonal BaTiO3. A tremendous increase in the efficiency of obtaining the correct structure is achieved when a cost function based upon this new approach is applied to these problems.

The crystal structure of K2Zn(PO3)4 was determined and refined using the Rietveld method based on the isostructure model of K2Cu(PO3)4. This compound belongs to the monoclinic system with space group Cc and lattice parameters of a=11.0941(2) Å, b=12.5215(3) Å, c=7.6597(2) Å, and β=102.47(2)°. The chemical formula unit per unit cell is Z=4 and the calculated density is 2.938(3) g∕cm3. Zigzag [PO3]∞ chains formed along the a axis, and their period contains eight PO4 tetrahedrons.

A ternary phase was revealed in Al-Ni-Re in a small compositional range around Al73.5Ni18.5Re8. Using powder X-ray diffraction and electron diffraction, it was found to have an orthorhombic structure with a=10.048(3) Å, b=15.423(8) Å, and c=8.367(3) Å.

A new ternary phase, Er2Cu10.9Ga6.1, has been found in the Er-Cu-Ga phase diagram. X-ray powder diffraction data were successfully refined based on a rhombohedral Th2Zn17 structure type (space group R-3m, No. 166) with cell parameters a=8.6627(1) Å, c=12.6824(2) Å, and Z=3. Er2Cu10.9Ga6.1 exhibits a paramagnetic Curie-Weiss behaviour down to 2 K with a trivalent character of Er atoms.