Single crystals of rhombohedral bismuth tri-iodide grown by physical vapor transport are possible candidates for room-temperature detectors. Previously reported, low angle reflections in X-ray diffraction patterns of various BiI3 starting powders are attributed to the BiI3 structure from Rietveld analysis. Accordingly, the lattice parameters of stoichiometric BiI3 are determined as a0=7.5192±0.0003 Å and c0=20.721±0.004 Å at room temperature. It also appears that lattice parameter determination using Rietveld refinement can lead to significant errors if experimental aberrations are present and their nature and magnitude are unknown. A modified internal standard technique is applied to the data set prior to Rietveld refinement for more reliable lattice parameter determination.

The title compound was identified as the major phase in a corrosion deposit by indexing its powder pattern, and locating an isostructural vanadium(II) compound in the NIST Crystal Data Identification File. The identity of the compound was confirmed by a Rietveld refinement. Hexaaquairon(II) trifluoromethanesulfonate crystallizes in the monoclinic space group C2/m, with a=18.6415(14), b=6.9291(5), c=6.5938(5) Å, β=104.742(6)°, V=823.68(10) Å3, and Z=2. The structure consists of alternating layers of octahedral hexaaquairon(II) cations and triflate anions. The cations and anions are linked into layers parallel to the bc plane by hydrogen bonds. Each water molecule donates two protons to sulfonate oxygens, and each sulfonate oxygen acts as an acceptor of two protons. A reference powder diffraction pattern is reported.

X-ray powder diffraction data for a new potassium sodium silicate Na1.3K0.7Si2O5 are reported. The sample was prepared by calcining a mixture of NaOH, KOH, and sodium silicate (SiO2/Na2O=3.54, moisture content=60%) at 873 K for 2 h. The crystallographic data obtained by using the whole-powder-pattern decomposition method are Na1.3K0.7Si2O5, monoclinic, P21/c, a =4.8426(1) Å, b = 8.6892(2) Å, c = 11.9686(3) Å, β=90.373(2)°, V=503.60(2) Å3, Z=4, Dx = 2.51 g/cm3.

Two compounds with compositions around n=14 and n∼5.4 (n=Bi/Mo molar ratio) have been prepared by solid-state reaction with five heating/grinding cycles at 800 °C. The lattice constants of both compounds can be related to the fluorite-type structure of δ-Bi2O3. Bi14MoO24 has been indexed as an orthorhombic pseudotetragonal (√2×√2×1) superstructure: a=7.812 (±0.005) Å, b=7.762 (±0.005) Å, c=5.7716 (±0.0007) Å (but a+b=15.5750±0.0020). For orthorhombic (3×5×3) Bi38Mo7O78: a=16.8236 (±0.0027) Å, b=28.6182 (±0.0045) Å, c=16.9082 (±0.0027) Å.

Legislation in the United States and Canada requires labelling of products containing ≥ 0.1 wt.% crystalline silica. Kaolin clays are used in a variety of industries and usually contain low levels of total (i.e., respirable plus non-respirable) quartz, even after beneficiation. X-ray diffraction procedures have been developed here which are suitable for the quantification of total quartz in commercial kaolins with accuracy sufficient to satisfy the legislation. Separation and analysis of the respirable fraction is not addressed in this paper; however, the procedures described would be applicable to such samples if sufficient were available. Use of the 50.1° 2θrather than the 26.6° 26 (CuKα) quartz peak avoids most of the potential problems of overlap with reflections from other accessory minerals. It is shown that profile fitting techniques and optimised experimental procedures allow the determination of quartz in bulk samples to ± 0.03 wt.% (95% confidence) at the 0.1 wt.% level, and ± 0.1 wt.% at the 1.0 wt.% level, with tolerable data collection times.

X-ray powder diffraction data for chioroquine sulphate monohydrate [7—chloro—4—(4—diethylamino—1—methylbutylamino)—quinoline sulphate monohydrate, C18H26C1N3· H2SO4 · H2O] have been determined. Crystals of chioroquine sulphate monohydrate are orthorhombic, space group P212121 with a=9.0134(7), b=11.7417(6), c= 19.850(1) Å, Z=4, and Dx= 1.378 g cm−3. The F30 index is 121 (0.0062, 40).

The trihydrated potassium trioxalato-chromate(III), K3(Cr(C2O4)3).3H2O, crystallizes in the monoclinic system with:

the space group is P21/c.

The absorption of X-rays in a heterogeneous material depends on the linear absorption coefficients and volume fractions of the components, and on die geometrical peculiarities of their distribution. The latter is called the microabsorption effect, it can be separated into a bulk and a surface contribution. Within the framework of a well-defined stochastic structure model, the bulk contribution to the microabsorption is calculated for arbitrary random multiphase systems in terms of dependence on volume fractions and mean chord lengths of particles. Expressions are derived which are suitable for eliminating the experimental errors of scattering intensities caused by the bulk contribution of microabsorption.

If only one wavelengtii of radiation is used, the mean chord lengths of the phases of the sample must be determined by other experimental techniques. A method is proposed to overcome this difficulty by using two or more wavelengths of radiation; this correction procedure works without the knowledge of the particle sizes of the phases.

The X-Ray powder diffraction patterns of three franckeite specimens from Bolivia all lack the 2.91 and 2.82 Å reflections of 100 intensity reported in PDF 15-25. A new indexed pattern is given for the franckeite of the San José mine, Oruro.

Citation analysis of the articles that appeared in the first five volumes of the journal Powder Diffraction showed that it is clearly a journal of crystallography with strong ties to materials science, mineralogy and analytical chemistry. This specific orientation makes Powder Diffraction invaluable in the existing network of scientific journals.

Accurate, digitized, spectral distribution data are given for CuKα radiation, comprising the profiles of CuKα1, CuKα2 and CuKα3,4. Three consistent analytical procedures are detailed for locating the peak of an X-ray emission line and are found to be superior to the conventional graphical centerline method.