Eight phosphates and arsenates of manganese have been synthesized and examined using powder X-ray diffraction in order to update or extend the current powder diffraction data files. The studied compounds are MnPO4·H2O, MnAsO4·H2O, LiMnPO4(OH) LiMnAsO4(OH), LiMnAsO4, Mn2As2O7) MnAsO4, and Mn(PO3)3. The powder patterns have been indexed and the cell data are reported.

Three members of the family [CuC15H11N3)X2]·nH2O [X−=NCO (n=1), NCSe and N3 (n=ø)], C15H11N3=2,2′:6′,2″ – terpyridine (terpy), have been prepared by reaction in solution. Crystal data determined widi the aid of single crystal methods, powder diffraction data, and densities determined by flotation methods are presented.

A conventional Bragg-Brentano type diffractometer was equipped with a stepping motor, a timer, and a scaler, and an MC68000 Motorola microprocessor which controls the diffractometer functions. The microprocessor was programmed to operate the diffractometer in a step-scanning mode, to check a datum and to communicate with a process control computer, e.g. a PDP 11/44 or a Micro VaxII computer.

Three orthovanadates ATh2(VO4)3with A = Li, Na, Ag have been synthesized by solid state reaction. Single crystals of AgTh2(VO4)3were obtained. This compound is isotypic with sheelite whose space group is I41/a(88). The two other compounds (A = Li, Na) have a zircon type structure: I41/ amd(141). Unit-cell parameters and powder diffraction data for the three compounds are reported.

A comparison between the results of ab initio structure determination from X-ray powder diffraction data of a new cadmium hydroxide nitrate, Cd5(OH)8 (NO3)2·2H2O (SG C2/m), and those obtained from single crystal data is presented. The powder diffraction pattern has been analysed by an indexing method and fitting techniques. A total of 119 unambiguously indexed reflections has been extracted and used in subsequent treatment. The power of powder techniques to index the pattern and to find the structure model by normal Patterson and Fourier methods is clearly shown. The refinement of approximate coordinates has been carried out by the Rietveld method (444 reflections). The comparison of results with those obtained from single crystal data (2218 reflections) shows that the precision of positional parameter values is lower by a factor of 10, on average, in the powder study. These results are discussed in terms of crystallographic parameters (number of reflections used, number of parameters to refine, contrast between atoms) and, also, in terms of sample dependent properties (preferred orientation effect, impurity). Finally, the crystal structure has been derived from powder data with a precision probably sufficient for most purposes.

Pearson VII functions, some of the most useful descriptions of the intensity distribution within the X-ray powder reflection, have been used to study distortion in the perovskite-type structure of KMnF3. Separate full-widths, Δ, at half-maximum intensity, and Pearson exponents, m, were taken for the low- and high-angle sides of the profiles. The background was assumed to be linear. For the distorted structure, summation was made over all overlapping lines that might possibly contribute to the observed profile. Measurements were performed using a powder diffractometer with a specially adapted electronic system consisting of an automatic data recorder and a method, developed at this laboratory, for transferring data to an IBM PC/AT computer. By these means it could be shown that at 10° K the crystal structure of KMnF3distorts from cubic to monoclinic.

The crystal structure of the tysonite-type superstructure of β-PrF3 has been studied by X-ray powder diffraction and high-energy electron diffraction from single crystals. The crystal data are: a = 7.0795(1) Å, c = 7.2380(2) Å, Z = 6, hexagonal system, space group (No. 165), ρcalc = 6.28 g cm−3. Atomic parameters and interatomic distances are presented from the final refinement with Rconv = 1.72%.

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).