Two ammonium copper molybdates having the stoichiometric compositions (NH4)2Cu(MoO4)2(NH3)2 and (NH4)2Cu(MoO4)2 have been synthesized from aqueous solutions. The compounds crystallize in the triclinic system with space group . Crystal data and indexed X-ray powder diffraction data are reported for both phases.

An X-ray detector chain consisting of a Xe-filled proportional detector followed by a pulse height analyzer tuned to 8.1 keV may register energies between 5 and 45 keV, although with a low efficiency at the edges. For diffraction experiments on single-crystalline substrates, these diffracted intensities can be significant. In the high-energy range, regions of even higher intensity are found due to the so-called escape process. In the diffraction angle scan of an (001) oriented Si single-crystal measured with a low (fixed) incidence angle, we have identified 21 peaks, originating from three different diffraction processes: diffraction from white radiation, diffraction observed via an escape process, and crystal truncation rod scattering. These peaks interfere with diffraction studies if such a single crystal is used as a substrate for polycrystalline samples. A great reduction in the substrate background and removal of most of the substrate diffraction peaks is achieved with a graphite monochromator or with a graphite monochromator together with a β-filter.

Diffraction peak broadening analyses were carried out on diffraction profiles of several reflections from hot-pressed α-Al2O3 containing 29, 18 and 10 volume % β-SiC whiskers. The data were analyzed and compared using four different integral breadth methods for microstrain and crystalline size. All four methods gave comparable results, within an order of magnitude, for the microstrains in each phase: (2-15 × 10−4 for the matrix and (6-19 × 10−4 for the whiskers). Microstrains in both matrix and whiskers decreased with decreasing volume % of whiskers for all four methods. Trends in the crystallite size were less consistent but for the matgrix, an incrfease from ∼665 to 1565Å was found with decreasing whisker content using DeKeijser's method.

Neodymium ammonium hydroxynitrate, Nd(OH)2NO3.(NH4NO3)0.5.H2O, has been investigated by means of X-ray powder diffraction. Unit cell dimensions were determined by indexing programs, from diffractometer data obtained with strictly monochromatic CuKα1 radiation. An I orthorhombic cell was found: a = 24.577 (4) Å, b = 7.1488 (16) Å, c = 3.8211 (9) Å. It is shown that the h 1 1 reflections present a selective line broadening.

A new amine zinc hydroxide nitrate has been synthesized and investigated by means of X-ray powder diffraction. The monoclinic unit cell dimensions are a = 20.781(3) Å, b = 6.2151(9) Å, c = 5.4952(6) Å, β = 92.24(1)° (space group C2/m with Z = 2). The crystal structure has been refined by the Rietveld method using the structure of the related dihydrated phase as a starting model (Rp = 0.092 and RF = 0.068 for 372 reflections). The structure is characterized by octahedra [Zn(OH)6] describing a brucite-type layer, with one-quarter of the metal atoms missing, and by tetrahedra [Zn(OH)3(NH3)] located above and below the empty octahedra. The complex positive sheet has the formula [Zn3octa(OH)8Zn2tetra(NH3)2]2+ and the cohesion of the structure is realized through hydrogen bonding.

Powder-diffraction data were collected for a Chinese sample of ferrimolybdite. This mineral is orthorhombic, space group Pmmn or Pm21n, with a = 6.665(2), b = 15.423(5), c = 29.901(8), and V = 3074(1) Å3.

The effect of solid emulsifiers, added at the level of 10%, on the lattice parameters of tristearin and trilaurin, has been studied by powder X-ray diffraction method. The presence of sorbitan monostearate and glycerol-l-stearate affects slightly the lattice constant a in tristearin; on the other hand, although sorbitan monostearate causes an increase in a of trilaurin, glycerol-l-stearate does not. The presence of sorbitan monolaurate and glycerol-l-laurate affect a of trilaurin similarly to the long chain emulsifiers.

A correlation between the effect on a and the increase in melting point has been found.

The presence of the emulsifier does not alter drastically the lattice dimensions of the fat. The slight dissimilarity in crystal structure between tristearin and trilaurin is confirmed by the diverse effects of the emulsifiers on the internal structure of the fat.

The structure of [Pd(NH3)4]Cr2O7 has been determined ab initio from conventional X-Ray powder diffraction data by the Patterson method. The cell is monoclinic (space group P21/c, Z = 4), with a = 7.771(3) Å, b=11.578(1) Å, c=11.852(4) Å, and β= 105.50(4)°. Refinements of 57 parameters by the Rietveld method, using 852 reflections lead to RB = 0.032, RP = 0.075, and Rwp = 0.092. The structure is built up from PdN4 square planes linked to Cr2O7 groups by hydrogen bonds. Hydrogen atoms could not be located.