This study examined basal peak irrationalities according to boundary conditions of the hectorite basal diffraction unit (BDU), which were recognized as the total assembly of 2:1 phyllosilicate layer plus interlayer material. The hectorite basal profiles were computer-simulated using the three kinds of BDU settings identified from the middle of octahedral sheets in the nearest neighbor (centrosymmetric model), the middle of interlayers in the nearest neighbor (centrosymmetric model), and a basal oxygen plane to the margin of interlayer in contact with the next phyllosilicate layer (non-centrosymmetric model). In the results of simulations, irrationality and asymmetry of the hectorite basal peaks relied straightforwardly on the BDU scattering modulations for the non-Bragg angles containing information on the synergic scattering events of phyllosilicate layer and interlayer material. Among the concerned BDU boundaries, the non-centrosymmetric model more effectively represented the real hectorite profile than the two previously reported centrosymmetric models.

X-ray powder diffraction data for the high temperature phase of NaBi3V2O10 obtained from in situ high temperature XRD studies are presented. NaBi3V2O10 undergoes a phase transition from triclinic to monoclinic at about 600 °C. The unit cell parameters of the high temperature monoclinic phase at 600 °C are: a=12.3899(21), b=5.5642(10), c=7.1543(18) Å and β=98.393(16)°, V=487.94(13) Å3 and Z=2, ρcal=6.20 g∕cc. On further increasing the temperature, it partially decomposes to a γ-Bi4V2O11 type phase. The details of this phase as well as the stability of NaBi3V2O10 are discussed.

The value assignment of candidate Standard Reference Material (SRM®) 57b Silicon Metal provided an opportunity to develop an alkali reaction procedure as a precursor to borate fusion for the preparation of test specimens from the metal powder for X-ray fluorescence spectrometry (XRF). Suggested for this purpose by Blanchette in a 2002 Advances in X-ray Analysis article [45, 415–420 (2002)], the alkali reaction uses LiOH∙H2O to convert Si to Li2SiO3. Lithium silicate is fused with lithium borate flux without damage to platinum ware. Once specimens are fused and cast as beads, calibration standards are prepared to closely match the compositions of the specimens, allowing a linear calibration for each analyte. The XRF method yields results that are directly traceable to the mole through NIST SRM spectrometric solutions. The method was validated in two ways. First, the reaction was used on older SRMs for Si metal: SRM 57 and SRM 57a. Second, XRF results for candidate SRM 57b were compared to results obtained using prompt gamma-ray activation analysis (PGAA) and inductively coupled plasma optical emission spectrometry (ICPOES). Bias tests show the XRF results are accurate for the elements Al, S, Ca, Ti, Cr, Mn, Ni, Cu, and Zr. Levels of S, Ca, Cr, and Cu in candidate SRM 57b are near the limits of quantification of the borate fusion method. Iron results may be subject to a low bias. Phosphorus is not quantitatively retained during the alkali reaction and borate fusion. These elements, plus B, which cannot be determined after borate fusion, are listed in manufacturing specifications for Si metal.

An incident beam X-ray collimator for Mao-Bell type diamond anvil cell (DAC) has been developed. Alignment of the collimator is carried out in situ while viewing the image of the collimated X-ray spot formed on a thin layer of fluorescent material spread on the diamond anvil culets with the help of a microscope. Special precaution has been taken to meet the radiation safety requirements during alignment and routine use. This collimator is of immense help for laboratory based high pressure X-ray diffraction experiments.

Single-phase samples of La1−xCaxMnO3 compounds have been synthesized by solid-state reaction. Detailed Rietveld analysis of powder X-ray diffraction data showed that La1−xCaxMnO3 undergoes a structural phase transformation from R-3c to Pnma at X=0.05–0.075. There is a linear variation of lattice parameters as a function of calcium concentration. The slope of this linear variation changes at X=0.6. A correlation between observed Mn-O bond lengths, corresponding to different compositions, and possible magnetic phases is discussed.

In the course of our research on normal alkanols, the crystal structure of 1-pentanol has been solved by applying Patterson-search methods to laboratory powder X-ray diffraction data recorded on a curved position-sensitive detector (CPS120) at 183 K. The crystal structure was refined with the rigid-body Rietveld least-squares method. The cell is monoclinic, space group P21∕c, Z=4, and the cell parameters are a=15.592(9) Å, b=4.349(1) Å, c=9.157(1) Å, β=104.7(7)°, V=600.6(3) Å3. There is one molecule in the asymmetric unit with the O–H bond in gauche conformation with respect to the alkyl skeleton. Packing is defined by the hydrogen bonds linking the 1-pentanol molecules along zigzag chains parallel to b.

X-ray powder diffraction data for the tetraphosphinic Si(CH2PPh2)4 silane are reported. Its crystal and molecular structures were determined by simulated annealing and full-profile Rietveld refinement methods. Si(CH2PPh2)4 was found to have tetragonal symmetry with P-421c space group. The lattice parameters were determined to be a=17.211(2) Å, c=7.553(1) Å, V=2237.5(5) Å3. The crystal structure was found to contain isolated Si(CH2PPh2)4 molecules. In each Si(CH2PPh2)4 molecule, the central Si atom was fixed at the −4 symmetric position bearing four CH2PPh2 branches. This environment was confirmed by 31P CP/MAS NMR measurements. Thermo-diffractometric measurements in the 20–120 °C range were also used to estimate the linear and volumetric thermal expansion coefficients (∂ ln V/∂T=1.8×10−4 K−1), typical for very “soft” materials.

A series of Internet-distributed audio/visual recordings for learning crystallographic analysis of powder diffraction data is discussed. These recordings provide a compact mechanism for distributing educational information. Such presentations provide hands-on discussion beyond what is usually presented in instructional texts. In some cases similar material can be presented with HTML text, but recordings can be created with significantly less effort and are superior for software demonstration.

A new micro-X-ray flourescence (XRF) instrument was developed in combination with an atomic force microscope (AFM). A small pinhole of 5 or 10 μm was made on the AFM cantilever. The center of the micro-X-ray beam generated by a polycapillary X-ray lens was passed through the pinhole. The present experiment demonstrated that the size of the original X-ray beam of 48 μm produced by the polycapillary lens was reduced to about 10 μm. This instrument enables both observation of the surface morphology by the AFM and elemental analysis by micro-XRF.

Internal stresses and textures of electroplated copper films (t=2, 8, 15, 30, 45, and 60) electrodeposited on Al substrates were studied using X-ray diffraction techniques. Results show that the stresses in the films are tensile. The 8 to 60 μm thick films have (220) fiber texture, in good agreement with strain energy minimization calculation. Results also show that a further rotational alignment of the fiber-textured grains was developed, and small amounts of the fiber-textured grains have their (2, −2, 0) planes aligned parallel to the flow direction of the electrodeposited currents. The degree of the rotation alignment increases with film thickness. Values of stress and the degree of texture of copper films were found to be adjustable using an ultrasound technique. Internal stress and the degree of the (220) texture decrease significantly by applying an ultrasound treatment during the electrodeposition process.

Crystal structure of Ca1.1Co1.9(PO4)2 was successfully determined from laboratory X-ray powder diffraction data (Co Kα) using direct methods and the Rietveld refinement. The crystal structure was found to be monoclinic (space group P21∕n, Z=4) with lattice dimensions of a=1.452 67(5) nm, b=0.494 34(1) nm, c=0.867 50(3) nm, β=92.316(1)°, and V=0.622 45(3) nm3. The final reliability indices calculated from the Rietveld refinement were Rwp=3.93%, Rp=3.02%, RB=4.10%, and S=1.48. Both Co and Ca atoms were distributed over the 2a and 2d sites with a preference of Ca at the 2d site. The coexistence of Co and Ca on the 2a and 2d sites is indispensable for stabilizing Ca1.1Co1.9(PO4)2 in the Ca3(PO4)2-Co3(PO4)2 system.

X-ray powder diffraction data for the trigonal form of disilver trihydrogen paraperiodate, Ag2H3IO6, are reported. The cell parameters are a=5.941 89(3), c=12.7253(1) Å, V=389.089(6) Å3, and ρ=5.65 g cm−3 for Z=3. A full-profile Rietveld refinement confirms the monophasic nature of the sample and the presence of two-dimensional corrugated layers of the A2BO6 type linked by hydrogen bonds. Short unsupported Ag–Ag contacts (about 3.02 Å) of the argentophilic type are also shown.