Rietveld quantitative X-ray diffraction analysis of the fly ash Standard Reference Materials (SRMs) issued by the National Institute of Standards and Technologies was performed. A rutile (TiO2) internal standard was used to enable quantitation of the glass content, which ranged from 65% to 78% by weight. The GSAS Rietveld code was employed. Precision was obtained by performing six replicates of an analysis, and accuracy was estimated using mixtures of fly ash crystalline phases and an amorphous phase. The three low-calcium (ASTM Class F) fly ashes (SRM 1633b, 2689 and 2690) contained four crystalline phases: quartz, mullite, hematite, and magnetite. SRM 1633b also contained a detectable level of gypsum, which is not common for this type of fly ash. The high-calcium (ASTM Class C) fly ash, SRM 2691, had eleven crystalline phases and presented a challenge for the version of GSAS employed, which permits refinement of only nine crystalline phases. A method of analyzing different groups of nine phases and averaging the results was developed, and tested satisfactorily with an eleven-phase simulated fly ash. The results were compared to reference intensity ratio method semiquantitative analyses reported for most of these SRMs a decade ago.

An external standard method using mica for angular calibration of powder diffractometers is described. This is useful especially when standard referee materials certified by the US National Institute of Standards and Technology are not accessible.

The powder pattern of calcium galactarate tetrahydrate (CaC6H8O8·4H2O) is presented. The compound was found in white wine stored for 4 years. A Rietveld refinement using the atomic coordinates from a single crystal study as starting values was refined with 55 parameters and without preferred orientation to RB=5.97%, RF=4.44%, Rp=10.39%, and Rwp=13.43% for 84 reflections. Crystal data: Mr=320.14, orthorhombic, Pcan, a=7.3359(1) Å, b=11.6296(3) Å, c=15.0978(6) Å, V=1288.05(6) Å3, Z=4, Dx=1.651 g/cm3, λ(CuKα1)=1.54060 Å, μ=46.76 cm−1.

New powder X-ray diffraction data for magnesio-, ferro-, and manganaxinite, obtained from samples closely corresponding to the three end-members of the axinite mineral group, were obtained using a conventional Bragg–Brentano diffractometer. Space group is P 1¯. Powder patterns were indexed using Peacock's normal orientation, which gave: a=7.1381(3), b=9.1626(4), c=8.9421(4) Å, α=91.903(4), β=98.105(3), γ=77.468(4)° for magnesioaxinite; a=7.1479(4), b=9.1962(5), c=8.9576(4) Å, α=91.857(4), β=98.177(4), γ=77.359(4)° for ferroaxinite, and a=7.1849(4), b=9.2152(5), c=8.9765(4) Å, α=91.761(4), β=98.153(4), γ=77.150(4)° for manganaxinite. Peacock's orientation has been adopted in all recent structural and crystal chemical studies of axinite, but it differs from that reported on the JCPDS cards (29-344, 27-076 and 27-084, respectively). New data include an increased number of indexed peaks.

We report precision X-ray powder-diffraction (XRD) data of single phase pure Ti2ZrAl. Ti2ZrAl samples were prepared by an arc melting method and annealed at 1000 °C for 30 days. XRD analysis was carried out on these samples and it was found that Ti2ZrAl has a DO19 structure (space group P63/mmc, No. 194). The lattice parameters are found to be a=5.961±0.001 Å and c=4.793±0.001 Å.

Powder diffraction data were collected for a synthetic zinc molybdate of composition Na(OH)Zn2(MoO4)2·2.5H2O. The material is monoclinic, space group C2/m, with a=9.4543(12), b=6.3492(7), c=7.6453(11), β=115.899(13), and V=412.83 Å3.

The titled compound, Hg2[Fe(CN)5NO], was synthesized and studied by X-ray powder diffraction, infrared spectroscopy, Mössbauer spectroscopy, and atomic force microscopy. The results arising from this study indicate that this compound is anhydrous and crystallizes in the P222 orthorhombic symmetry. The unit cell parameters were quantified as a=16.5905(9) Å, b=12.3145(8) Å, and c=8.7576(5) Å. The measured and calculated density values are Dm=1.149 g/cm3 and Dc=1.145 g/cm3, respectively, with Z=2.