We report here the fabrication and characterization of ultra-long AlN whiskers by physical vapor transport method. The obtained whiskers are 1–3 µm in diameter and up to millimeters in length. The whiskers grow along the [0001] crystallographic direction and are well crystallized. They exhibit a strong ultraviolet emission at 345 nm, the shortest wavelength reported in AlN whiskers or nanowires. Our results indicate that these large scales of AlN whiskers are less contaminated by oxygen and other impurities compared with the previously reported ones, which may find wide applications in fabricating ultraviolet optoelectronic devices.

In this study, CeO2 nanowires–reduced graphene oxide hybrids (CeO2 NWs–RGO) were synthesized by a green hydrothermal method using CeO2 NWs and graphene oxide (GO) as raw materials. During the process of reduction of GO, hydrothermal condition with supercritical water provides thermal and chemical factors to synthesize RGO. The photocatalytic experimental results show that the CeO2 NWs–RGO hybrids exhibit enhanced photocatalytic activity for degradation of Rhodamine B (RhB) under UV-light irradiation. It is found that the degree of photocatalytic activity enhancement strongly depends on the mass ratio of RGO in the hybrids, and the remarkable photocatalytic activity is 20 times that of pristine CeO2 NWs when the loading amount of RGO is 8.0 wt%. The enhancement of photocatalytic activity can be attributed to the excellently elevated absorption ability for the dye through π–π conjugation as well as the effective inhibition of the recombination of photogenerated electrons because of the electronic interaction between CeO2 NWs and RGO sheets.

A new Ca1/3Sb1/6Bi1/2PO4 “CaSb0.50Bi1.50(PO4)3” phosphate has been synthesized by conventional solid-state reaction techniques at 900 °C in air atmosphere. Their crystallographic structures were determined at room temperature from X-ray powder diffraction (XRPD) data using the Rietveld analysis. CaII 1/3SbV 1/6BiIII 1/2PO4 material possesses the high-temperature BiPO4 monoclinic structure variety. It crystallizes in monoclinic system with P21/m space group and the cell parameters are: a = 4.9358(1) Å, b = 6.9953(2), c = 4.7075(1) Å, and β = 96.2(1)°. Their structure can be described as composed of alternating edge-sharing AO8 (A = Ca, Sb, Bi) bisdisphenoids and PO4 tetrahedra forming chains parallel to the b axis. Every AO8 polyhedron is surrounded by six PO4 and every PO4 tetrahedron is surrounded by six AO8 polyhedra. Infrared spectroscopic study was used to obtain further structural information.

The structure of a birefringent andradite–grossular sample was refined using single-crystal X-ray diffraction (SCD) and synchrotron high-resolution powder X-ray diffraction (HRPXRD) data. Electron-microprobe results indicate a homogeneous composition of {Ca2.88Mn2+0.06Mg0.04Fe2+0.03}Σ3[Fe3+1.29Al0.49Ti4+0.17Fe2+0.06] Σ2(Si2.89Al0.11) Σ3O12. The Rietveld refinement reduced χ2 = 1.384 and overall R (F2) = 0.0315. The HRPXRD data show that the sample contains three phases. For phase-1, the weight %, unit-cell parameter (Å), distances (Å), and site occupancy factor (sof) are 62.85(7)%, a = 12.000 06(2), average <Ca–O> = 2.4196, Fe–O = 1.9882(5), Si–O = 1.6542(6) Å, Ca(sof) = 0.970(2), Fe(sof) = 0.763(1), and Si(sof) = 0.954(2). The corresponding data for phase-2 are 19.14(9)%, a = 12.049 51(2), average <Ca–O> = 2.427, Fe–O = 1.999(1), Si–O = 1.665(1) Å, Ca(sof) = 0.928(4), Fe(sof) = 0.825(3), and Si(sof) = 0.964(4). The corresponding data for phase-3 are 18.01(9)%, a = 12.019 68(3), average <Ca–O> = 2.424, Fe–O = 1.992(2), Si–O = 1.658(2) Å, Ca(sof) = 0.896(5), Fe(sof) = 0.754(4), and Si(sof) = 0.936(5). The fine-scale coexistence of the three phases causes strain that arises from the unit-cell and bond distances differences, and gives rise to strain-induced birefringence. The results from the SCD are similar to the dominant phase-1 obtained by the HRPXRD, but the SCD misses the minor phases.

The crystal structure of copper(ii) citrate monohydrate (C6H4O7Cu2·H2O) has been solved from a mixture powder diffraction pattern. Approach to indexing, structure solution and Rietveld refinement of multiphase diffraction patterns is discussed. Rietveld refinement is carried out employing free-atom refinement and rigid body refinement.

Two additional forms of K2FeF5 are disclosed and characterized by powder diffraction. One (form-IV) adopts a new A2MF5 structural type, space group C2/m, a = 13.0919(2) Å, b = 5.7311(1) Å, c = 7.3114(1) Å, β = 118.241(1), and Z = 4, it is obtained from the thermal evolution of form-III, isostructural with Rb2FeF5, space group Pnma, a = 7.3964(2)  Å, b = 5.6779(1) Å, c = 11.5445(3) Å, and Z = 4. Both forms are compared to two previously reported polymorphs. The III → IV transition is topotactic, conserving the same zigzag cis-connected octahedral (FeF5)n2n− chains after an ~90° rotation and 1/2b translation of half of them.

The dichlorodioxido(4,4′-dimethoxycarbonyl-2,2′-bipyridyl)molybdenum(VI) complex was prepared from molybdenum(VI) dichloride dioxide and 4,4-dimethoxycarbonyl-2,2-bipyridyl in CH2Cl2 obtaining a clear green solution. The molybdenum complex was separated by precipitation with ethyl ether. The XRPD pattern for the new compound showed that the crystalline compound belongs to the monoclinic space group P21 /c (No 14) with refined unit-cell parameters a = 12.104(1) Å, b = 14.933 (2) Å, c = 11.010 (2) Å and ß = 115.409° (9). The volume of the unit cell is V = 1797.6 (3) Å3.

Experimental X-ray powder diffraction data, unit-cell parameters, and space group for norethindrone, C20H26O2, are reported [a = 20.7484(12) Å, b = 12.1678(9) Å, c = 6.5561(2) Å, α = β = γ = 90°, unit-cell volume V = 1655.17(16) Å3, Z = 4 and space group P212121]. All measured lines were indexed and are consistent with the P212121 space group. No detectable impurity was observed.

Experimental X-ray powder diffraction data, unit-cell parameters and space group for schisanhenol, C23H30O6, are reported [a = 14.6157 Å, b = 12.8801 Å, c = 11.4907 Å, unit-cell volume V = 2163.14 Å3, Z = 4, and space group P212121]. All of the measured lines were indexed and are consistent with the P212121 space group. No detectable impurities were observed.

Experimental X-ray powder diffraction data, unit-cell parameters, and space group for levetiracetam, C8H14N2O2, are reported [a = 9.197(5) Å, b = 8.006(0) Å, c = 6.289(3) Å, β = 108.457(3)°, unit-cell volume V = 439.261 Å3, Z = 2, and space group P21]. All measured lines were indexed and are consistent with the P21 space group. No detectable impurity was observed.

The compound 2-ethyl-6-(pyridin-4-yl)-7H-indeno[2,1-c]quinoline (2) (chemical formula C23H22N2) was synthesized through the free-solvent oxidation reaction mediated by elemental sulfur from the corresponding 2-ethyl-6-(pyridin-4-yl)-5,6,6a,11b-tetrahidro-7H-indeno[2,1-c]quinoline (1), an adduct easily obtained, using the Lewis acid-promoted [4 + 2] cycloaddition reaction. Preliminary molecular characterization was performed by Fourier transform-infrared and gas chromatography-mass spectrometry. The X-ray powder diffraction (XRPD) pattern for the title compound was analyzed and found to be crystallized in monoclinic system, space group P21/n (N° 14) with refined unit-cell parameters a = 20.795 (8) Å, b = 7.484 (2) Å, c = 10.787 (2) Å and ß = 93.96° (2). The volume of the unit cell is V = 1674.8 (6) Å3.

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.

Thiocolchicoside (THC) is an important active pharmaceutical ingredient (API) used as a muscle relaxant because of its anti-inflammatory and analgesic effects. The only entry for a THC-related compound present in the Cambridge Structural Database (CSD) corresponds to a THC ethanol solvate hydrate (refcode: THCLCS). The diffraction pattern recorded for the THC raw material (C27H33NO10S·xH2O) is different from the pattern calculated using the THCLCS crystallographic data contained in the CSD. The indexing of the THC raw material pattern, produced an orthorhombic unit cell with a  = 28.018(7) Å, b  = 12.519(2) Å, c  = 8.519(1) Å, and V = 2988.01 Å3. All the diffraction maxima of the powder pattern of a phase recrystallized in water (C27H33NO10S·2H2O) can be indexed in an orthorhombic cell with a  = 25.264(4) Å, b  = 13.537(3) Å, c  = 8.553(1) Å, and V = 2925.12 Å3. Thermogravimetric analysis shows that this compound is a dihydrate phase. Upon heating, a new anhydrous phase (C27H33NO10S) with a monoclinic cell and unit cell parameters: a  = 17.090(5) Å, b  = 19.485(5) Å, c  = 8.526(3) Å, β = 100.30(2)°, and V = 2793.34 Å3 is obtained.

Veatchite polytypes were properly identified from several localities relying solely on micro powder diffraction data. Diagnostic differences in their respective calculated patterns gave reliable identification results when compared with measured data. This permitted the confirmation of co-existing veatchite-1A and -2M on the same specimen from the Billie Mine, Inyo County, California as flat elongated crystals (-1A) and flat rhombic plates (-2M), respectively. On the specimen from the Sterling Borax Mine (Lang), type-locality for veatchite-2M, the polytype veatchite-1A was confirmed from radiating rhombic plates. From the type specimen for veatchite-1A (rhombic plates), collected from the borate deposit in Emet, Turkey, an additional unknown polytype of this mineral was discovered, but lacks suitable material for a complete characterization. At the Penobsquis deposit near Sussex in New Brunswick, Canada, only veatchite-2M was encountered. The area between 20 and 25°2θ holds the following diffraction signatures: -1A (two sets of double peaks at approximately 21.5 and 24.5°2θ), -1M (single peaks at 20 and 23°2θ) and -2M (double peaks at 20 and 23°2θ). The unknown polytype from Emet, Turkey differs from polytype-1A in that same range by having single peaks at the 21.5 and 24.5° instead of double peaks.

Synchrotron X-ray diffraction images are increasingly used to characterize not only structural and microstructural features of polycrystalline materials, but also crystal preferred orientation distributions. Diffraction data can be analyzed quantitatively and efficiently with the Rietveld method and here the detailed procedure is reported from the experiment to the calibration of the two-dimensional detector and full analysis of the sample. In particular, we emphasize the advantage of doing the calibration inside the Rietveld least-squares fitting instead of a preliminary graphical calibration. Then the procedure is described to quantify crystal preferred orientations with the Rietveld method implemented in software “Materials Analysis Using Diffraction”. The process is illustrated for a US “nickel” coin, a 75 at.% copper 25 at.% nickel alloy with face-centered cubic structure and a strong cube texture.

Early in September 2013, only a few months away from the International Year of Crystallography (2014), nearly 230 scientists from more than 15 different Countries gathered in Como, for an International Conference co-organized by the Italian, Spanish, and Swiss Crystallographic Associations, presenting their most recent crystallographic results in variety of fields, in basic and applied Science. This brief account highlights the topics discussed during the conference, and the future of the European crystallographic research, with its relevance to distinct fields of physics, chemistry, biology, materials, and earth science, as well as in preservation of cultural heritage.