Ferrivauxite, ideally Fe3+ Al2(PO4)2(OH)3·5H2O, is an oxidized equivalent of vauxite, Fe2+ Al2(PO4)2(OH)2·6H2O, and forms oxidation pseudomorphs after that mineral. It occurs in association with sigloite and crandallite at the Llallagua tin deposit, Bolivia. It is triclinic, space group P1̄, with a = 9.198(2), b = 11.607(3), c = 6.112(2) Å, α = 98.237(9), β = 91.900(13), γ = 108.658(9)°, V = 609.7(5) Å3, Z = 2. Strongest reflections of the powder X-ray diffraction pattern are [dobs in Å(Iobs)(hkl)]: 10.834(100)(010), 8.682(24)(100), 8.242 (65)(110), 6.018(28)(001), 5.918(23)(1̄10), 5.491 (30)(1̄20), 4.338(26)(200), 2.898 (32)(300). The structure was refined to R1 = 0.0369 for 3244 observed reflections. Twinning occurs on {010}. Ferrivauxite is isotypic with vauxite but with positional disorder of the Fe1 site and some of the oxygen sites. Disorder is also indicated by the infrared spectrum. One of the water molecules in vauxite is deprotonated in conjunction with the oxidation process and becomes a hydroxyl group. Ferrivauxite is translucent to transparent, has a golden brown colour with a pale yellow-brown streak and vitreous lustre. It is brittle with an irregular fracture and shows no cleavage. The Mohs hardness is estimated to be ∼3½ by comparison with vauxite. D(calc.) is 2.39 g cm–3 for the empirical formula Fe3+0.94Mn0.01Al1.98P2.05O8(OH)3 · 5H2O, obtained by electron-microprobe analysis in wavelength dispersive spectroscopy mode. The mineral is optically biaxial negative with α = 1.589(1), β = 1.593(1), γ = 1.596(1); the refractive indices are higher than those of vauxite.

A new quaternary compound AlCeCo2Ni2 was synthesized and studied by means of X-ray powder diffraction technique. The powder pattern of AlCeCo2Ni2 was indexed and refined, giving a hexagonal structure, space group P6/mmm (No. 191) with the CaCu5 structure type. a = 4.9242(2) Å, c = 4.0524(1) Å, V = 85.1 Å3, Z = 1, ρx = 7.85 g cm−3, F30 = 130.2(0.010, 30), and RIR = 0.71(2).

A new quaternary compound PrAlFeNi3 was synthesized and studied by means of X-ray powder diffraction technique. The powder pattern of PrAlFeNi3 was indexed and refined, giving a hexagonal structure, space group P6/mmm (No. 191) with the CaCu5 structure type, a = 5.1132(2) Å, c = 4.0737(1) Å, V = 92.19 Å3, Z = 1, ρx = 7.20 g cm−3, F30 = 173.61 (0.0054, 32) and RIR = 0.77.

A new ternary compound Ho2AlGe3 was synthesized and studied by means of X-ray powder diffraction technique. The powder pattern of Ho2AlGe3 was indexed and refined, giving an orthorhombic structure, space group Pnma (No. 62) with the Y2AlGe3 structure type: a = 6.743 98(8) Å, b = 4.163 73(5) Å, c = 17.5834(2) Å, V = 493.74 Å3, Z = 4, ρ x  = 7.73 g cm−3, F 30 = 202.7 (0.004, 37), and RIR = 1.21.

New X-ray powder diffraction patterns for two cholesterol derivatives, cholest-4-ene-3,6-dione and cholest-4-en-3-one are reported in the range 0<2θ<115°. Both compounds crystallize in similar monoclinic cells in space-group P21, with unit cell parameters a=10.481(3) Å, b=8.0354(8) Å, c=14.677(3) Å, β=105.265(7)°, V=1192.5(4) Å3 for C27H42O2, and a=10.703(2) Å, b=7.8750(6) Å, c=14.660(3) Å, β=105.205(14)°, V=1192.4(4) Å3 for C27H44O. The patterns, confirmed by single-crystal studies, do not match the PDF 17-1144 and PDF 10-649. A fitting of the overall parameters was performed with Fullprof using the atomic parameters obtained from single-crystal studies.

X-ray powder diffraction data for N,N'-diphenylguanidinium nitrate, within the temperature range of 103–293 K, are reported. The pattern at 293 K was confirmed by a fitting of the overall parameters performed with FULLPROF using the atomic parameters obtained from single-crystal studies. The compound is orthorhombic, space group Pna21 (33), with unit-cell parameters a=1.7058(4) nm, b=1.3933(3) nm, c=0.5821(1) nm, and V=1.3834(6) nm3. The unit-cell parameters for the other six temperatures measured were determined by performing pattern matching with FULLPROF. The unit-cell volume contracted on cooling from 1.3834(6) nm3 to 1.3403(4) nm3. The thermal expansion tensor was calculated from the changes of the unit-cell parameters with temperature. The elements of the thermal expansion tensor at 293 K are α11=125(4),α22=57(9), and α33=82(3)×10−6 K−1.