An experimental X-ray powder diffraction pattern was produced and analyzed for imipenem monohydrate, an antimicrobial pharmaceutical agent. Although there are no experimental powder patterns in the ICDD PDF-4/Organics Database, there is one powder pattern calculated with single-crystal X-ray diffraction data from the Cambridge Structural Database. Here, we report the refined experimental powder diffraction data for imipenem monohydrate. These data for imipenem monohydrate are consistent with an orthorhombic crystal system having reduced unit-cell parameters of a = 8.2534(3) Å, b = 11.1293(4) Å, and c = 15.4609(6) Å. The resulting unit-cell volume, 1420.15(15) Å3, indicates four formula units per unit cell. Observed peaks are consistent with the P212121 space group.

Single crystals of Sm0.55Sr0.45Mn0.4Fe0.6O3 were grown by an optical floating zone technique in an oxygen atmosphere. The powder X-ray diffraction pattern for the grown crystal revealed single-crystalline nature. The lattice parameters and atomic structure were refined and indexed using a General Structure Analysis System (GSAS) to an orthorhombic structure with lattice parameters a = 5.4415 (32) Å, b = 7.6994 (27) Å, c = 5.43868 (28) Å, and space group Pnma.

The crystal structure of eltrombopag olamine Form I has been solved and refined using synchrotron X-ray powder diffraction data and optimized using density functional techniques. Eltrombopag olamine crystallizes in the space group P21/n (#14) with a = 17.65884(13), b = 7.55980(2), c = 22.02908(16) Å, β = 105.8749(4)°, V = 2828.665(11) Å3, and Z = 4. The crystal structure is dominated by columns of hydrogen-bonded cations and anions along the short b-axis. van der Waals interactions bind the columns together. Two H atoms of each ammonium group in the ethanolammonium cations participate in strong hydrogen bonds, and the third H forms weaker bifurcated H-bonds. The powder pattern has been submitted to ICDD® for inclusion in the Powder Diffraction File™ (PDF®).

X-ray powder diffraction data, unit-cell parameters, and space group for alogliptin benzoate, C18H21N5O2·C7H6O2, are reported [a = 28.8260(8) Å, b = 9.9654(4) Å, c = 8.1477(8) Å, α = 90, β = 90, γ = 90°, unit-cell volume V = 2340.57 Å3, Z = 4, ρcal = 1.3097 g cm−3, and space group P212121]. All measured lines were indexed and are consistent with the P212121 space group, No detectable impurities were observed.

The crystal structure of indacaterol hydrogen maleate has been solved and refined using synchrotron X-ray powder diffraction data, and optimized using density functional techniques. Indacaterol hydrogen maleate crystallizes in space group P-1 (#24) with a = 8.86616(9), b = 9.75866(21), c = 16.67848(36) Å, α = 102.6301(10), β = 94.1736(6), γ = 113.2644(2)°, V = 1273.095(7) Å3, and Z = 2 at 295 K. The crystal structure consists of layers of cations and anions parallel to the ab-plane. Traditional N–H⋯O and O–H⋯O hydrogen bonds link the cations and anions into chains along the a-axis. There is a strong intramolecular charge-assisted O–H⋯O hydrogen bond in the non-planar hydrogen maleate anion. There are also two C–H⋯O hydrogen bonds between the anion and cation. The cation makes a strong N–H⋯O hydrogen bond to the anion, but also acts as a hydrogen bond donor to an aromatic C in another cation. The amino group makes bifurcated N–H⋯O hydrogen bonds, one intramolecular and the other intermolecular. The hydroxyl group acts as a donor to another cation. The powder pattern has been submitted to ICDD for inclusion in the Powder Diffraction File™ (PDF®).

Metallic filaments with sub-micrometer diameters have recently been fabricated using novel materials fabrication techniques at NRL. The specimens are enshrouded in a glass sheath and all efforts to obtain structural information from these samples with conventional x-ray sources have been negative. By using synchrotron radiation on a wiggler beam line, x-ray diffraction data have been obtained from samples with diameters of 0.22, 0.09, 0.07, and 0.04 μm. The two thicker samples were found to be single crystals with a structure consistent with that of normal Bi. Single crystal diffraction peaks obtained from the 0.07 μm sample are incompatible with the Bi-1 or any other known structure of Bi. We have provisionally identified this as Bi-X.

X-ray reference powder patterns and structures have been determined for a series of cobalt-, nickel- and zinc-containing niobates, Co(NixZn1−x)Nb4O12 (x = 0.2, 0.4, 0.6, 0.8). The Co(NixZn1−x)Nb4O12 series crystallize in the space group of Pbcn, which is of the disordered columbite-type structure (α-PbO2). The lattice parameters range from a = 14.11190(13) to 14.1569(3) Å, b = 5.69965(6) to 5.71209(13) Å, c = 5.03332(5) to 5.03673(11) Å, and V = 404.844(8) to 407.296(17) Å3 from x = 0.8 to 0.2, respectively. Co(NixZn1−x)Nb4O12 contains double zig-zag chains of NbO6 octahedra and single chain of (Ni,Zn,Co)O6 octahedra run parallel to the bc-plane. Within the same chain the NbO6 octahedra share edges, while the adjacent NbO6 chains are joined to each other through common oxygen corners. These double NbO6 chains are further linked together along the [100]-direction through another (Co,Ni,Zn)O6 units, via common oxygen corners. The edge-sharing (Co,Ni,Zn)O6 also forms zig-zag chains along the c-axis. Powder X-ray diffraction patterns of this series of compounds have been submitted to be included in the Powder Diffraction File.

The X-ray fluorescence analysis of a trace element under a grazing incidence condition has been developed using synchrotron radiation. The interference effect plays an important role for determining the depth distribution of the elemental concentration. The elemental distribution above, on or below the material surface has been studied. The glancing angle dependence of the X-ray fluorescence signal around the critical angle strongly reflects the elemental distribution, and can be used to determine the position of the element of interest.

A commercial Empyrean X-ray diffractometer was adapted for combined grazing incidence X-ray fluorescence analysis (GIXRF) measurements with X-ray reflectivity (XRR) measurements. An energy-dispersive silicon drift detector was mounted and integrated in the angle-dependent data acquisition of the Empyrean. Different monochromator/X-ray optics units have been compared with the values obtained by the Atominstitut GIXRF + XRR spectrometer. Data evaluation was performed by JGIXA, a special software for combined GIXRF + XRR data fitting, developed at Atominstitut. A sample consisting of a ~50 nm nickel layer on a silicon substrate was used to compare the performance criteria (i.e. divergence and intensity) of the incident beam optics. An Empyrean X-ray diffractometer was successfully refitted to measure both GIXRF and XRR data.

The compound Th13Te24O74 was prepared by three independent methods, namely, thermal decomposition of ThTe2O6 in oxygen and argon and direct solid-state reaction of ThO2 and TeO2. The X-ray powder diffraction patterns of the three products, by and large, are similar, except for some differences in intensities and extra diffraction lines. The thermal decomposition of ThTe2O6 was carried out in the streams of oxygen and argon by thermogravimetry at a heating rate of 5 K/min in the temperature range of 725–840 °C. The solid-state reaction of ThO2 and TeO2 (13:24) was carried out in a sealed ampoule at 700 °C. The measured density of this compound is 8.23 g/cm3. An orthorhombic lattice with unit cell parameters, a=11.310±0.005 Å, b=14.064±0.006 Å, c=9.056±0.004 Å, and volume of 1440.419±1.088 (Å)3 was determined for this compound.

Preliminary study of performance of an HPGe detector with an ion implanted entrance window in the spectrometry of the ultralowenergy x-rays is presented.

For the first time it has been shown that almost symmetric photopeaks and absence of low energy tailing can be obtained in this region from HPGe detectors.

Automated powder diffractometers are beginning to come into general use. The principal reason for automating or purchasing an automated powder diffractometer is to increase the speed and accuracy of the analysis. Three principal methods are used. The first is that a multisample changer increases the through-put on the instrument since the unit can be operated unattended during the evening. The second is the diffractometer can be scanned at faster rates when digital data are collected, as opposed to the analog method of using a strip chart recorder. The third is the elimination of reading the peak positions and intensities from the strip charts. These readings would typically have to be tabulated manually for later interpretation. Another reason for having an automated powder diffractometer is for experiments where digital data are necessary to make the analysis practical. These experiments include routine quantitative analysis, radial distribution functions, Fourier profile analysis, and signal averaging to bring out very weak diffraction peaks.

A new ESCA (electron spectroscopy for chemical analysis) instrument has been developed to provide high sensitivity and efficient operation for laboratory analysis of composition and chemical bonding in very thin surface layers of solid samples. High sensitivity is achieved by means of the high-intensity, efficient X-ray source described by Davies and Herglotz at the 1968 Denver X-Ray Conference, in combination with the new electron energy analyzer described by Lee at the 1972 Pittsburgh Conference on Analytical Chemistry and Applied Spectroscopy. A sample chamber designed to provide for rapid introduction and replacement of samples has adequate facilities for various sample treatments and conditioning followed immediafely by ESCA analysis of the sample.

Examples of application are presented, demonstrating the sensitivity and resolution achievable with this instrument. Its usefulness in trace surface analysis is shown and some “chemical shifts” measured by the instrument are compared with those obtained by X-ray spectroscopy.

Total Reflection X-ray Fluorescence Analysis (TXRF) has been proved to be well suited for the energy dispersive analysis of light elements, as B, C, N, O, F, Na, Mg,.,. using a special spectrometer. It is equipped with a Ge(HP) detector offering a sufficient detection efficiency from 180 eV upwards. The obtainable detection limits especially of the light elements are mainly influenced by the excitation source, which should provide a large number of photons with an energy near the K-absorption edge of these elements (from 200 eV upwards). Commercially available X-ray tubes do not offer characteristic X-rays in that range. In former experiments a windowless X-ray tube was built to prevent the low energy X-rays from being attenuated in the Be window. Experiments have been performed using Cu as anode material.

The electron density distribution maps for CaF2 and TiO2 (rutile) were obtained from profile fitting of powder diffraction data by a Maximum Entropy Method (MEM) analysis. The resultant electron density maps show clearly the nature of the chemical bonding. In order to interpret the results, the nuclear density distribution was also obtained for rutile from powder neutron diffraction data. In the electron density map for rutile obtained by HEM analysis from the X-ray data, both apical and equatorial bonding can be seen. On the other hand, the nuclear density of rutile Is very simple and shows the thermal vibration of nuclei.

Ila group metal - Zr pcrovskitc type compounds (MZrO3, M=Ba. Sr and Ca) and other oxides were studied by XPS to know the effects of M atoms to Zr atoms. And the feasibility of using XPS and high-resolution XRF for the coordination analysis of Zr atoms was examined for some kinds of stabilized zirconia. An almost linear relationship between the energy of Zr 3d peaks and the radii of Ila group metal ions was found, and, a simple model to interpret this relationship has been proposed. However, no relationship between the energy shifts of Zr 3d spectra or Zr Lα1, 2 spectra and the coordination numbers of Zr atoms in the several Zr oxide compounds was found. Thus, the coordination analysis using XPS or high-resolution XRF is not feasible.

Asymmetric crystal topography (ACT) in reflection and transmission electron microscopy (TEM) were used to investigate the crystal quality of both typical GaAs substrates and AIGaAs epitaxial layers grown on these substrates. ACT topographs of large sections of 75mm GaAs wafers revealed the presence of several types of crystal defects. All the GaAs wafers surveyed showed the presence of low angle grain boundaries which usually extended over a significant portion of the wafer. In addition, the well-known cell structure dislocation network was always observed in semi-insulating wafers. Less common but often present were inclusions and precipitates. The n-type (Si doped) substrates showed a typical cross-hatched pattern. ACT topography also easily revealed the crystal damage caused by wafer grinding.

Epitaxial layers of AIGaAs were grown by conventional molecular beam epitaxy on these characterized GaAs substrates. ACT topography was used to examine separately the epitaxial layers and substrate crystals. Layers which were grown below the pseudomorphic limit showed crystal features identical to the GaAs substrate on which they were grown and the substrate was unaffected by the presence of the epitaxial layer. AJAs layers which were grown above the pseudomorphic limit were severely dislocated: TEM confirmed the presence of misfit dislocations at the interface. The substrate in this case also showed the presence of crosshatching indicating the the extension of the dislocation strain field into the substrate.

Urea complexes consist of a channel made up of hydrogen-bonded urea host molecules into which a variety of guest molecules can fit to form a crystalline complex. The urea host can accommodate, one at a time, a variety of guests having the requisite size and shape. The stability of the resulting complex is a function of the properties of the guest molecule. A procedure has been devised which produces pure complex free of any uncomplexed urea or host molecules in solution. The insoluble crystalline complexes formed from the solution of urea and guest molecule in methanol established a dynamic equilibrium. When the crystals of complex are removed from the solution, dissociation to urea and guest occurs to an extent, depending upon the dissociation constant of the complex. If the dissociation constant, KD, is very low, undetectable quantities of uncomplexed urea form along with complex. If the dlissoclation constant is high, extensive amounts of urea form in the presence of complex. Characteristic interplanar spacing s are obtained for a urea complex irrespective of the guest molecule present. The pattern obtained for the hexagonal complex is completely different from the pattern obtained for tetragonal urea. X-ray examination of a homologous series of compounds gives, for each partially dissociated complex, spacings for both urea and complex. The relative intensities of urea and complex spacings permit the estimation of the stability of such a complex compared to that of other homologues.

A special measurement technique has been developed to measure very low level iodine concentrations. The gas and water samples to be analysed are taken from the POSEIDON facility at PSI where retention of iodine in water pools in conjunction with light water reactor safety analysis is under investigation. The amount of iodine was measured by means of a Total Reflectance X-Ray Spectrometer (TXRF).