X-ray powder diffraction data are reported for a series of isomorphous compounds of [Ln2(CrO4)3(H2O)5]·2H2O, where Ln=La, Pr, Nd, Sm, or Eu. The compounds crystallize in monoclinic space group P21/c (No: 14) with Z=4. Refined unit cell parameters and indexed powder diffraction patterns are given.

A FORTRAN 77 program to perform full matrix least-squares refinement of unit cell parameters from powder diffraction patterns showing incommensurate supercell reflections is described. The code is completely general, being applicable to any crystal system, and can refine all three unit cell edges and angles and, in the presence of an incommensurate supercell, can refine the components of the modulation vector along all three reciprocal axes. Estimated standard deviations on all the refined parameters are calculated analytically.

The design and construction of Geiger-Müller counters which will respond reliably to Mo K x-rays is described. The impulses are amplified and recorded mechanically with the aid of a thyratron circuit. The amplifying and counting circuit, and the counting mechanism, are also described. The time of recovery of the counters has been determined by the use of an oscillograph and found to be less than 0.001 sec. when the proper values are used for the resistance and capacitance of the counter circuit. It is shown that for counting rates up to 600 per minute there is less than a 1 percent correction due to the fact that the impulses are random in nature. Several fundamental tests are described, which have been applied to the counter and the circuit. These tests have shown the counter and the circuit to be a reliable method of measuring x-ray intensities. Graphs are shown of the diffraction patterns of NaCl and KC1 taken by means of the counters. These graphs duplicate the well-known diffraction patterns of these materials, thus giving additional evidence of the reliability of the counters.

A method for quantitative characterization of a phase's depth distribution is discussed in detail. Both model-independent and model-dependent nonlinear least squares technique methods were developed; in addition, an inverse Laplace transformation method is presented to solve the problem directly in mathematics. The methods can also be used for samples with preferred orientation. Furthermore, the technique is expanded to the technique of computed depth profiling of XRD patterns; then the depth profiles of other structural information that is based on the peak intensity, peak position, and line profile can be determined. A feasibility test was also performed.

A program has been written for rapid lattice parameter refinement which is designed to be applied to components in a mixture. This FORTRAN program employs a linear least-squares technique and is applicable to crystal systems with symmetry orthorhombic or higher. In addition to lattice parameters, a 2θ-zero can also be refined. Either approximate lattice parameters or a minimal set of indexed lines can be used as input. An example is given of its application to a AuMn two phase system.

Powder samples for diffraction studies of selected materials have been prepared in this laboratory during the past 15 years using a commercial, slow-speed, diamond saw. The materials powdered include a wide range of ferrous and transition metal alloys as well as geological substances. Before sectioning begins, fresh oil is poured into the oil tray of the saw and the diamond, rim-impregnated, copper blade thoroughly cleaned. A typical blade is 10 cm in diameter and 3 mm thick. Powder produced as the blade cuts through the sample collects in and settles to the bottom of the oil tray. The oil, which bathes the sample surface during cutting and surrounds the powder debris after discharge into the tray, serves to prevent oxidation of most materials.

The kalipyrochlore (K,Sr,Na,Ca,H2O)2−m(Nb,Ti)2−xO6−wY1−n, with (0<m<0.8, x∼0.2, w = 0 and 0.2<n<1) from Lueshe, Zaire is a defect pyrochlore species whose A-site weakly depleted. The measured powder diffraction is presented with a calculated figure of merit F(30) = 74.7(0.010,39). The structure has been refined by single-crystal from X-ray diffraction data collected on a Huber four-circle diffractometer and by Rietveld analysis from X-ray powder diffraction data. The slightly weathered crystal (studied by single crystal) has a cubic pyrochlore-type structure with the same atomic positions and a unit-cell parameter a = 10.603(5) Å, space group (S.G.): Fd3m. The highly weathered crystal (studied by Rietveld) has the same cubic pyrochlore-type structure except for the oxygen position. The oxygen moved from the 48f position with x, y, z equal to 0.284, 0, 0 to x = 0.308(5), y = 0.024(6) and z = –0.028(9). The cell parameter is a = 10.569(6)±0.0007 Å. These modifications of positions induce a distortion of the A-site into an hexagonal bipyramid and an elongation of the B-site along the c axis of the octahedron.

X-ray powder diffraction analysis of Diltiazem Hydrochloride C22H26N2O4S·HCl reveals that the compound crystallizes in an orthorhombic unit cell with the powder data unit cell parameters of a=9.08(1), b=42.09(4), c=6.03(1) Å, V=2305 Å3. The unit cell dimensions determined by single crystal diffraction analysis agree well with those of powder diffraction analysis. Samples prepared under different crystallization conditions yielded the same powder patterns.

This report is one of a series on the nomenclature for spectrochemical analysis issued by the International Union of Pure and Applied Chemistry. It concerns a new notation for X-ray emission lines and absorption edges, to be called IUPAC NOTATION, which replaces the existing Siegbahn notation. It is based upon the energy level designation and has the advantage of being simple and easy to apply to any kind of transition. Moreover, it is consistent with the notations used in electron spectroscopy.

The document first discusses the terms currently used in X-ray spectroscopy and then describes the principles of the IUPAC notation with reference to the X-ray levels and the X-ray transitions. The correspondence between Siegbahn and IUPAC notations for all X-ray lines is given in a table. Finally, the document gives the units and conversion factors used in the X-ray range.

Three isotopic orthovanadates MTh2 (VO4)3 with M = K, Rb, Cs have been syndiesized by solid state reaction. Single crystals of K Th2 (VO4)3 and Rb Th2 (VO4)3 were obtained. These compounds are isotypic with the corresponding orthophosphates: monoclinic, space group C2/c, Z = 4. Unit-cell parameters for die diree compounds were determined. Powder diffraction data for each phase are reported.

A Bi2O3 compound which is unknown to date has been synthesized at 800 °C on a BeO substrate. α-Bi2O3 at 800 °C undergoes a phase transition to a metastable new compound named ω-Bi2O3 which in turn transforms to stable δ-Bi2O3 at 900 °C. X-ray powder diffraction data were collected, indexed, and refined in order to obtain a unit cell (probable space group P1¯: a=7.2688(4), b=8.6390(6), c=11.9698(8) Å, α=87.713(6), β=93.227(6), γ =86.653(4)°. This compound is of interest for the thick films circuits and sensors technology.

An indexed powder diffraction pattern and related crystallographic data are reported for cefotaxime sodium salt: 5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid, 3-[(acetyloxy)methyl]-7-[[(2amino-4-thiazolyl)(methoxyimino)-acetyl]amino]-8-oxo, monosodium salt, [6R−[6α,7β(Z)]], C16H16N5NaO7S2. The unit cell dimensions were determined from diffractometer methods, using monochromatic CuKα1 radiation, and evaluated by indexing programs. The monoclinic cell found for cefotaxime sodium was a=13.063(2) Å, b=8.916(2) Å, c=9.726(2) Å, β=107.34(2)°, Z=2, space groups: P21 (No. 4) or P21/m (No. 11), Dx=1.467 g/cm3.

This paper further confirms that the direct measurement of diffraction angles at different temperatures by using the X-ray diffractometer is better than measurement of the lattice parameters for the rapid and accurate determination of the linear thermal expansion of silicon. High purity silicon has the linear expansion coefficient, α= (2.45±0.05) × 10−6/°C at room temperature. This value does not change for doped P-type and N-type silicon.