A new and improved sample holder for use with powder X-ray diffractometry has been developed. This holder is made from a semiconductor grade silicon single crystal cut perpendicular to the [911] axis, i.e., Si (911). This crystal meets most of the basic requirements of an ideal zero background plate, with practically no interference lines. The pattern obtained, by using this crystal as background plate, is very clean, and even very low-intensity Bragg reflections of samples can be detected easily.

Thulium (Tm) doped barium yttrium ytterbium fluoride (BaYYbF8:Tm) thin films have been deposited on (100) silicon (Si) or (100) and (111) gallium arsenide (GaAs) substrates. When deposited on (100) Si, with an intermediate amorphous silicon dioxide (SiO2) layer, the BaYYbF8:Tm film was found to be polycrystalline, crystallizing in a previously unobserved cubic phase with a lattice constant a = 11.4208 (9) Å . Films deposited on GaAs, with an intermediate calcium fluoride (CaF2) layer, showed a high degree of planar orientation. Pole figure analysis revealed that the BaYYbF8:Tm films deposited on CaF2/GaAs are in-plane aligned dependent upon the substrate orientation.

Error quantities, defined earlier to estimate the accuracy of texture measurement, are used to define a probability criterion for correct indexing of powder diffraction diagrams. The criterion is based on the compatibility of pole density distribution functions of different (hkl) depending on the directions {θ,γ}(hkl) of the reciprocal lattice vectors r*(hkl). The criterion was applied to permutation of the indices and variation of the angles {θ,γ}(hkl) in the vicinity of the correct values. In fortunate case, these angles can be determined within a few degrees by minimizing the error quantities. The method works very well with strong textures but it is still applicable if only weak textures can be achieved. The method was tested with different crystal symmetries including cubic, hexagonal, orthorhombic, and monoclinic. It is concluded that the criterion can be successfully applied to all crystal symmetries. If a measuring technique based on a position sensitive detector is used, even multifold peak superpositions in tilted sample orientations can be resolved. The method can also be applied if some (hkl) cannot be separated experimentally.

Particle statistics in quantitative X-ray diffractometry relates to the number of particles (crystallites) contributing to the diffracted intensity for a given line. Variations in line intensity between replicate preparations of the same sample arise from statistical variations in the number of diffracting particles. The uncertainty in line intensity, and hence in quantitative estimates of analyte concentration, is termed the particle statistics error. A theoretical estimate of the error for stationary samples qives σPS=ξ[μ*〈v〉/c]1/2, where μ* is the mass absorption coefficient of the mixture, and 〈v〉 and c are the mean particle volume and mass concentration respectively of the analyte. The factor ξ is a function mainly of diffractometer geometry, but also contains contributions from rocking angle and reflection multiplicity. For measurements of the (112) quartz line with a Philips PW1050 vertical goniometer with 2o divergence slit and 0.3 mm receiving slit, ξ was calculated to be 116 g1/2 cm−5/2 for stationary samples. Three close-cut size fractions of quartz were prepared at various concentrations in a calcium carbonate matrix. Replicate preparations were measured and the standard deviation obtained as a function of particle volume and concentration. After correction for other contributing errors, including counting statistics and thermal fluctuations, the experimental value ξ=122±10 g1/2 cm−5/2 was obtained. The effect of sample spinning is considered briefly and predicted to reduce σPS by a factor of about 5. Experimentally, a reduction in σPS of about this order is observed, but the effect is rather variable.

Characterization of some crystalline species present in atmospheric particulate matter can be investigated by an X-ray diffractometric technique. According to the analytical strategy, filtering media suitable for collecting airborne particles must be selected. In order to recognize the X-ray diffraction patterns and consequently the inherent analytical interference of filtering media, a systematic X-ray diffraction evaluation of several substrates was performed. Although artifact formation during ambient sampling can occur on quartz and glass fiber filters, these filters were also included in the diffractometric characterization. In this work, commercial filters were thermally treated and submitted to X-ray diffraction scanning. Results have shown pronounced variations in the diffractometric profiles of each thermally treated substrate. The selection criteria for choosing the filtering media was established by considering their chemical and physical properties and also the crystalline species to be collected on them.

An improved backloading method to determine the reference intensity ratios of sedimentary minerals is presented. More than 50 reference intensity ratios of more than ten types of minerals formed in typical sedimentary environments were measured. Quantitative tests were performed on those minerals. Comparison of the results show that this method minimizes preferred orientation and improves quantitative precision (absolute deviation is less than 3%) so that it is an acceptable specimen loading method.

Powder X-ray diffraction data are reported for La0.6Sr0.4Co1−yFeyO3 (y=0.1, 0.25, 0.4, 0.6, 0.8, 1.0). The powders were prepared by thermal decomposition of metal-containing complex solutions. All compositions have rhombohedral unit cells. In hexagonal setting, the cell parameters are a=5.4388 Å, c=13.2355 Å for y=0.1; a=5.4427 Å, c=13.2542 Å for y=0.25; a=5.4530 Å, c=13.2838 Å for y=0.4; a=5.4769 Å, c=13.3175 Å for y=0.6; a=5.5057 Å, c=13.3918 Å for y=0.8; and a=5.5278 Å, c=13.4368 Å for y=1.0. The space group is probably R3c (167) for all compositions. The observed trends in the change of the pseudocubic cell parameter ac with increasing iron content can be explained in terms of substitution of Co4+ by Fe4+ when y<0.4, and substitution of Co3+ by Fe3+ when y≳0.4.

The X-ray powder diffraction patterns for tetramethylammonium bromide and iodide have been measured from near room temperature up to decomposition/sublimation. The unit cell parameters were refined and the coefficients of thermal expansion calculated. Unlike N(CH3)4Cl [M. Stammler, J. Inorg. Nucl. Chem. 29, 2203–2221 (1967)], N(CH3)4Br (1Br) and N(CH3)4I (1I) undergo no solid–solid transitions before decomposition/sublimation as was observed earlier by thermal analysis [S. S. Chang and E. F. Westrum, J. Chem. Phys. 36(9), 2420–2423 (1962); Coulter etal., J. Am. Chem. Soc. 62, 2845–2851 (1940); Xenopoulos etal., Mol. Cryst. Liq. Cryst. 214, 63–79 (1992)].

In the preparation of ceramic SrCe0.95Yb0.05O3−α great care was taken to obtain a homogeneous, carbonate free and dense material of exactly the given composition. The material is an important high-temperature protonic conductor (HTPC). X-ray powder diffraction data are reported. The cell parameters obtained are a=6.007(2) Å, b=12.296(3) Å, c=8.588(2) Å, cell volume 634.4(1) Å3, Z=8. The space group is most probably Pnma (62) and Dx=5.806(2) g/cm3. The bending strength of the sintered dense material is 175±6 MPa.

A well-crystallized sample of powdered KCl has been distributed among several laboratories in order to test the reproducibility of the lattice parameter measurement on different X-ray powder diffraction instruments. The precision of the determined unit-cell dimension is in the 10−5 Å range, while the discrepancies among the results from different laboratories using the same numerical analysis are at least one order of magnitude higher. It is shown that if different numerical analyses, including full pattern refinement, are used, values differing in the third decimal digit are obtained for the same data set.