A program is presented that removes broadening from X-ray diffraction spectra. An instrumental spectrum can be used to describe empirically the broadening to be removed, or a Gaussian, Cauchy, or Pearson-VII distribution can be used to analytically describe it. In either case, singlet or doublet forms can be generated. The program returns the deconvoluted spectrum, the reconstructed spectrum, and a sum-of-squares difference between the original and reconstructed spectra. Deconvolution is accomplished using a combination of least-squares, background, and smoothing criteria that minimizes the effect of random counting errors.

A complete set of d spacings, intensities, and h, k, l indexes for Ti2AlN has been determined from X-ray powder diffraction. The lattice parameters are a=2.989(2) Å, c=13.614(5) Å; in good agreement with previous work. The new set of results comprises seven reflections not present in the current Ti2AlN PDF card No. 18-70. Furthermore, a new set of relative intensities are reported that are in better agreement with the calculated values than they are with those listed in the PDF card.

2,4,6-Trimercapto-s-triazine, trisodium salt (ideally, Na3S3C3N3·9H2O), also known as TMT-55, is a white powder that is used to precipitate heavy metals from contaminated waters. Chemical analyses confirmed the nominal composition. TMT-55 crystals are uniaxial negative with indices of refraction (25 °C) of nε=1.520 and nω=1.675. The structure was determined by single-crystal methods at 25 and −110 °C. A powder pattern was determined and compared to a simulated pattern based on the 25 °C structure data. Crystal data at 25 °C are: R3;Z=6; a=17.600(1) Å and c=9.720(2) Å; V=2607.5(5) Å3; Dx=1.55 g/cm3.

Potassium hydrogen fluoride KHF2 is tetragonal at room temperature: a=5.667(1) Å, c=6.795(1) Å, d=2.38, Z=4, space group I4/mcm (No. 140). It gives a polymorphic transition at 196 °C to a cubic form: a=6.435(1) Å, Z=4, space group Fm3m, melts at 239 °C, and then dissociates into gaseous HF and solid KF.

Four compounds in the hexafluoroniobates IV series MNbF6 (M=Ca, Mg, Cd, Zn) have been synthesized by solid-state reactions. CaNbF6, MgNbF6, and the “high temperature” form of CdNbF6 are isostructural with f.c. cubic NaSbF6 (space group Fm3m). ZnNbF6 and the room temperature form of CdNbF6 are isostructural with rhombohedral LiSbF6 (space group R3¯). Syntheses and powder diffraction data are reported.

The crystalline structure of new TlSr2PrCu207−x was obtained at room temperature (300 K) and low temperature (100 K) from X-ray powder diffraction with CuKα radiation using Rietveld analysis. TlSr2PrCu207−x has an isotypical structure with TlBa2CaCu207 (1212). At 300 K, crystal data: Tl0.864Sr2PrCu2O6.75, Mr=727.811, the tetragonal system, P4/mmm, a =3.85404(5) Å, c = 12.1046(2) Å, V=179.80 Å3, Z=1, Dx =6.7218 g cm−3, μ =1143.922 cm−1 (λ = 1.54051 Å), F(000)=317.0, the structure was refined with 28 parameters to Rwp=5.29%, Rp = 3.65% for 3551 step intensities and Rb=7.40%, Rf=639% for 155 peaks, “goodness of fit” 5=3.05. At 100 K, crystal data: Tl0.858Sr2PrCu2O6.61, Mr=724.345, the tetragonal system, P4/mmm, a =3.84872(6) Å, c = 12.0771(3) Å, V=178.89 Å3, Z=1, Dx=6.7235 g cm−3, μ=1146.939 cm−1 (λ= 1.54051 Å), F(000) = 315.4, the structure was refined with 26 parameters to Rwp=6.70%, Rp=5.11% for 2926 step intensities and Rb=7.83%, Rf=6.70% for 131 peaks, “goodness of fit” S = 1.75.

A simple, practical search/match program, RIFRAN 85, has been written and implemented for the EMG 666B programmable calculator. The computer programs are written in EMG Assembler, which is identical to the assembler language for the Hewlett-Packard 9821 calculator. The EMG 666B is made in Hungary and has 8 kbytes of operational memory. The programs interactively provide qualitative phase analysis of X-ray powder diffraction patterns using standard files collected from published data and stored on a compact magnetic tape cassette. Each standard pattern can comprise up to 35 two-theta — intensity pairs. The identification procedure is based on the comparison of the diffraction data of the standard and of the unknown within limits imposed by user-established match and chemical criteria. This paper describes the algorithm used and the performance of the RIFRAN 85 identification system. The system's operation is illustrated using an example of phase analysis of a mineral sample.

Crystals of sodium copper oxalate dihydrate [Na2Cu (C2O4)2.2H2,O] were obtained by the gel method, from solutions of oxalic acid and copper chloride. The crystals form blue needles with idiomorphic faces of brilliant luster, permitting goniometric measurements and the determination of the morphology with the aid of crystallographic parameters. Optically the crystals are biaxial negative, 2V = 38°, with a weak dispersion r<v. The orientation of the indicatrix was determined using a universal stage.

Crystals of sodium copper oxalate dihydrate, Na2Cu (C2O4)2.2H2O, were apparently first obtained in 1929 by Riley. Gleizes et al. (1980) undertook a preliminary crystallographic study of crystals obtained by a different technique from Riley's. In the first case, a solution of 33.5 g/L of sodium oxalate was heated and then poured gradually into a nearly saturated solution of copper sulfate until slight turbidity appeared. The turbidity was eliminated and the solution clarified by the addition of a little more sodium oxalate solution. In this way Riley obtained a dark blue solution which after filtration yielded extremely fine sky-blue needle-like crystals, rarely more than 8mm long. In the method of Gleizes et al. (1980), copper oxalate was dissolved in an aqueous solution of sodium oxalate; those authors observed complete dissolution when the molar ratio of sodium oxalate to copper oxalate was near 2. By evaporating the solution, they obtained long, prismatic crystals whose crystallographic constants they determined.

In order to obtain crystals large enough for further crystallographic study, we set out to produce crystals of sodium copper oxalate by the gel method (Triché, 1984). We found that slow crystallization did encourage the formation of large crystals.

Indexed X-ray diffraction powder data for three homologous amphiphiles, sodium octyl sulfate (SOS), CH3[CH2]7 OSO3Na, sodium decyl sulfate, CH3[CH2]9OSO3Na (SDS), and sodium dodecyl sulfate CH3[CH2]11OSO3Na (SLS), are reported. Probable space groups for the three compounds are monoclinic P2[3], Pm[6], or P2/m[10]. Refined cell parameters were determined from powder data obtained with a Guinier Camera. Powder data are compared to existing patterns, PDF 4-10 (SOS) and 4-6 (SLS).

X-ray powder diffraction of Nitrofurantoin C8H6N4O5 reveals that the compound crystallizes in a monoclinic unit cell with the powder data unit cell parameters of a = 7.852(2), b= 6.497(1), c = 18.927(5) Å, β=93.15(2)°, V=964.1(2) Å3. The unit cell dimensions determined by single crystal agree very well with those of powder diffraction analysis. A comparison with the Powder Diffraction File (PDF) 34-1603 indicates that the present data provide a more precise match to the unit cell, include additional weak reflections, along with the indexing of the powder pattern.

The accuracy of the unit-cell parameters refined by using the whole-powder-pattern decomposition method is discussed. Powders of W, ZnO, TiO2, BaTiO3 Mg2SiO4, Al2SiO5 (+α-SiO2), and monoclinic ZrO2 were used as test samples. Two internal standard reference materials of Si and CeO2 and two types of powder diffractometers were used for data collections. The systematic peak-shift was corrected by determining the unit-cell parameters and the error function simultaneously during the whole-pattern-fitting. The estimated standard deviations for sample means ranged from <10 ppm (10−6) in cubic symmetry to 20∼50 ppm in monoclinic symmetry. These analyses could be carried out almost automatically in a computation time of less than l min for each sample on a workstation. The use of symmetric experimental profiles, obtained by the suppression of axial divergence, is very effective and of essential importance for improving the accuracy of unit-cell parameters.

A technique is presented utilizing an unmodified commercial X-ray diffractometer, equipped with a Bragg–Brentano geometry, for reducing preferred orientation effects in measured intensities during quantitative diffraction analysis. The diffractometer setup examined makes possible data acquisition with Θ fixed at 1° and 2Θ scanning the Bragg line. The results obtained with this technique are shown in the quantitative X-ray diffraction analysis of three international standards of carbonate rocks (401,402,403).