Relative angular precision in electron backscatter diffraction: A comparison between cross correlation and Hough transform based analysis

In the present study the relative angular resolution of an electron backscatter diffraction system based on Hough transform analysis has been determined with a silicon single crystal wafer. The resolution is found to be better than 0.1° and can be easily improved by repetition of measurements. A test measurement on a BaFe₂As₂ thin film, where disorientations of 0.1° and less are present, was performed using the cross correlation electron backscatter diffraction technique. The same measurement is evaluated with the Hough transform technique. Comparing both techniques give evidence of a relative resolution of better than 0.1°. However, in specimen areas with strain inhomogeneities a deviation along one rotation axis can be observed.     

Channeling‐enhanced EDX for polarity resolved crystal orientation determination

Using channeling‐enhanced energy‐dispersive X‐ray spectroscopy (EDX), we demonstrate polarity sensitive orientation determination of a non‐centrosymmetric crystal in the scanning electron microscope. The authors observe a characteristic asymmetry in the channeling‐enhanced, angle‐dependent EDX data of a GaAs sample, which is in good agreement to simulations using the dynamical theory of diffraction for the incident electron beam. This allows us to assign the orientation of the GaAs crystal according to the non‐centrosymmetric point group. The method shown here overcomes the limitation of a reduced point‐group sensitivity of electron backscatter diffraction patterns and electron channeling patterns for crystalline phases that contain atoms of approximately equal electron scattering cross sections.     

Crystal structure and characterization of a novel organic optical crystal: 4‐chloro‐3‐nitrobenzophenone

Single crystals of a novel organic material, 4‐Chloro‐3‐Nitrobenzophenone (4C3N) were grown from acetone solution employing the technique of controlled evaporation. 4C3N belongs to the Orthorhombic system, with a = 12.9665(11) Å, b = 7.4388(6) Å, c = 24.336(2) Å, α = β = γ = 90°. FT‐IR study has been performed to identify the functional groups. The transmittance of 4C3N has been used to calculate the refractive index n; the extinction coefficient K and both the real ε_r and imaginary ε_i components of the dielectric constant as functions of photon energy. The optical band gap of 4C3N is 2.7 eV. Thermo gravimetric analysis and differential thermal analysis have also been carried out, and the thermal behavior of 4C3N crystal has been studied. The mechanical properties have been investigated. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

X‐ray diffraction refinement of the crystal structure of anosovite prepared from leucoxene

The crystal structure of anosovite, (Ti_1.69Al_0.26Fe_0.05)³⁺(Ti_0.97Zr_0.03)⁴⁺O₅, prepared by carbothermal reduction of leucoxene under vacuum at 1450°C has been refined by Rietveld method using powder X‐ray diffraction data. It was found that it represents slightly monoclinically deformed pseudobrookite type structure with lattice parameters a = 9.8111 Å, b = 3.7509 Å, c = 9.9468 Å, β = 90.628°. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

The crystal structure of α‐SrGaBO4

A new compound α‐SrGaBO₄ has been synthesized by solid state reaction at high temperatures, and its structure has been solved by direct methods from powder X‐ray diffraction. α‐SrGaBO₄ has an orthorhombic system, Pccn space group, with lattice parameters a = 15.3154(7) Å, b = 8.9186(4) Å, c = 5.8130(3) Å, and Z = 8. The structure consists of infinite chains run parallel to the c axis and built up of GaO₄ tetrahedral and BO₃ triangles. The basic unit of these chains is a six ‐ membered Ga₂BO₈ ring formed by two GaO₄ tetrahedra and one BO₃ triangles. The Sr atom is bonded to eight oxygen atoms. The strontium atoms serve to hold the chains together through co‐ordination with oxygen atoms. DTA curve of noncrystalline glassy SrGaBO₄ was discussed. The XRD results show no phase transition occurs between ‐173 °C and 127 °C. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Single crystal growth of CaMg2(SO4)3 via solid‐ / gas‐phase reactions and its Nasicon‐related crystal structure

Crystals of the double sulfate CaMg₂(SO₄)₃ have been obtained by solid‐state reactions of stoichiometric amounts of anhydrous CaSO₄ and MgSO₄ in sealed and evacuated silica tubes with chlorine gas as mineraliser. The crystal structure was determined from single crystal X‐ray diffractometer data [P 6₃/m, Z = 2, a = 8.3072(4), c = 7.3057(8) Å, R [F² > 2σ (F²)] = 0.0317, wR (F² all) = 0.0785, 476 structure factors, 33 variable parameters] and consists of distorted [CaO₆] octahedra (3 symmetry), [MgO₆] octahedra (3 symmetry) and SO₄ tetrahedra (m symmetry) as single building units. The structure is made up of ¹_∞[CaO_6/2] chains of face‐sharing [CaO₆] octahedra that extend parallel to [001], alternating with columns of face‐sharing [MgO_3/1O_3/2]₂ dimers. Both types of chains are linked via corner‐sharing with SO₄ tetrahedra into a three‐dimensional framework structure. Although the compound crystallizes in a new structure type, it is topologically related to the NaZr₂(PO₄)₃ (Nasicon) structure, and a comparative discussion between both structural arrangements is given. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Synthesis and crystal structure determination of two dispiro compounds from laboratory x‐ray powder diffraction data

The crystal structures of the dispiro compounds 1,3,4,8,10,11‐Hexaphenyl‐13‐methyl‐1,2,8,9,13‐pentaazadispiro[4.1.4.3]tetradeca‐2,9‐dien‐6‐one ( 3a ) and 4,11‐Bis(4‐methoxyphenyl)‐13‐methyl‐1,3,8,10‐tetraphenyl‐1,2,8,9,13‐pentaazadispiro‐[4.1.4.3]tetradeca‐2,9‐dien‐6‐one ( 3b ) have been determined at room temperature from X‐ray powder diffraction data using the method of simulated annealing as implemented in the programs DASH and TOPAS. Subsequent Rietveld refinements using the data collected to 1.5 Å resolution yielded R‐Bragg values of 2.2% for ( 3a ) and 3.7% for ( 3b ). It was found, that both compounds crystallize in the monoclinc space group P 2₁/n with lattice parameters of a = 17.1656(5) Å, b =13.8128(3) Å, c = 16.1016(5) Å, and β = 103.7330(2)° for ( 3a ) and a = 17.2529(8) Å, b = 13.8729(5) Å, c =16.1287(10) Å, and β = 103.6910(3)° for ( 3b ). Both compounds exhibit a distorted hexagonal close type of packing (hcp) of the molecular centers of gravity. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

The effect of preflux bath additives on the morphology and structure of the hot‐dip galvanized coatings

The effect of CdCl₂, NiCl₂ and SnCl₂ on the morphology and on the structure of hot‐dip galvanized coatings was examined with optical microscopy, scanning electron microscopy and X‐ray diffraction, when these salts are added in the preflux bath. From this investigation it turned out, that the morphology of the coatings formed after fluxing in a preflux bath containing CdCl₂ is very similar to the morphology of the coatings formed in the usual flux, regardless of the concentration of the Cd salt and the solvent used (water or aqueous solution containing 50% ZnCl₂^.NH₄Cl) in the preflux bath. By contrast, Ni enhances the growth of small‐sized crystallites of the zeta‐phase instead of the columnar growth, and finally it results in reduction of the coating thickness. This phenomenon is likely to be affected by the NiCl₂ concentration but not by the solvent used (pure water or aqueous solution containing 50% ZnCl₂^.NH₄Cl). Finally, Sn addition seems to be inert with regard to the coating structure. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Synthesis and X‐ray crystal structure investigations of the complexes of a proton sponge with selected inorganic acids: Crystal structure of DMAN.HI complex

A series of ionic complexes of 1,8–bis(dimethylamino)naphthalene with selected inorganic acids such as HCl, HBr, HI, HSCN and HBF₄ were synthesised and thoroughly investigated by means of powder diffractometry and analytical methods. The crystallographic data for these compounds as well as the results of the structure solution by powder diffraction methods of the 1,8–bis(dimethylamino)naphthalene.HI complex, which crystallizes in the monoclinic system, S.G. P2₁/c (14), a=7.999(2)Å, b=23.053(3)Å, c=7.948(1)Å, β=99.63°, R_F=17.1%, R_wp=15.5%, are discussed and presented in this work. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Synthesis,crystal structure and third order nonlinear optical properties of bis(tetra‐n‐propylammonium) bis(2‐thioxo‐1,3‐dithiole‐4,5‐dithiolato)cuprate(II)

A novel bis (dmit) complex of copper (II), [(C₃H₇)₄N]₂[Cu(dmit)₂] ( 1 ), where dmit is 2‐thioxo‐1,3‐dithiole‐4,5‐dithiolate, was prepared and structurally characterized by X‐ray single crystal diffraction. The copper (II) atom is tetracoordinated by four dmit S atoms, forming a nearly square planar arrangement. The [Cu(dmit)₂]^2‐ anions and the [(C₃H₇)₄N]⁺ counter‐cations form a three‐dimensional solid‐state structure by C–H…S hydrogen bonds. The third‐order nonlinear optical properties of the complex were determined by picosecond Z‐scan technique at a wavelength of 1064 nm. The results indicate the compound exhibits reverse saturation absorption and self‐defocusing performance. The molecular second‐order hyperpolarizability γ is calculated to be as high as (1.8±0.2)×10^‐30 esu. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Growth and characterization of L‐valine ‐ a nonlinear optical crystal

The growth of a new nonlinear optical material L‐valine by solvent evaporation method is reported here. To grow good quality crystals pH value of growth solution has been optimized and solubility of L‐valine in different solvents and different pH values was determined. The grown crystals were characterized by IR, single crystal XRD, DTA and TGA, optical transmission and second harmonic generation (SHG) efficiency measurement. SHG efficiency of L‐valine was found equivalent to KDP and its transmission is 75%‐80% from ultraviolet to near IR region. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Crystal growth,structure and spectroscopic studies of a novel organic single crystal: L‐lysine p‐nitrophenolate monohydrate (LLNP)

A novel organic crystal, L‐lysine p‐nitrophenolate monohydrate (LLNP) has been grown successfully from an aqueous solution by the slow cooling method. Transparent single crystal of dimensions 22 × 12 × 12 mm³ has been obtained. The single crystal X‐ray diffraction has shown that LLNP belongs to the orthorhombic crystallographic system with space group P2₁2₁2₁. The functional groups and vibrational frequencies of the crystal have been identified using IR and Raman spectra. The proton and carbon configurations have been confirmed through ¹H‐NMR and ¹³C‐NMR spectra analyses. The UV‐Vis‐NIR transmittance spectrum for LLNP crystal has been recorded in the range from 200 to 2500 nm. The second harmonic generation (SHG) intensity of LLNP has been measured by powder SHG method and found to be as 4.2 times as that of KDP. The thermal properties have been studied by using thermo gravimetric (TG) and differential thermal analysis (DTA).     

The crystal structure of hexaammonium diacetyl‐octa‐molybdate tetrahydrate

The crystal structure of hexaammonium diacetyl‐octa‐molybdate tetrahydrate, (NH₄)₄₂[Mo₁₃₂O₃₇₂ (CH₃COO)₃₀(H₂O)₇₂] is documented. The crystals are triclinic, space group P‐1, with a=8.1018(16) Å, b=10.334(2) Å, c=12.238(2) Å, α=68.20(3)°, β=74.98(3)°, γ=67.25(3)°, V=869.3(3) ų, Z=1. The structure was solved by direct methods and refined by least squares methods to a Final R1 = 0.0374 and wR2 = 0.1074 for 3805 observed reflections with I > 2σ(I). The structure contains ammonium cations and isolated acetyl octamolybdate(6‐) anions, [Mo₈O₂₈(CH₃CO)₂]^6‐. The crystallographic data of the structure was deposited with the Cambridge Data Center as No. CCDC 249565. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

On the crystal structure type of 2 CsCl · CoCl2 · 2 H2O

The following three-component systems have been studied: CsCl MnCl₂ H₂O at 25 °C; 2 CsCl · CuCl₂ · 2 H₂O—2 CsCl · CoCl₂ H₂O at 10 °C and 2 CsCl · MnCl₂ · 2 H₂O—2 CsCl · CoCl₂ H₂O at 25 °C and 10 °C. It was established that Co²⁺-ions do not substitute isodimorphously the Cu²⁺-ions in the tetragonal salt 2 CsCl · CuCl₂ · 2 H₂O, whereas in the case of the triclinic salt 2 CsCl · MnCl₂ · 2 H₂O they can substitute isodimorphously the Mn²⁺-ions. The theoretical considerations supported by the results obtained allow to predict the existence of the double salt 2 CsCl · CoCl₂ · 2 H₂O as well as the type of its crystal structure — triclinic, space group P1 .     

Crystal structure and optical properties of 4‐nitrophenyl 4‐butoxybenzoate

The title compound, C₁₇H₁₇N₁O₅, has been synthesized and characterized by single crystal X‐ray analysis and UV‐Vis spectra. The crystals are monoclinic, P 2₁/c, a = 17.994 (5) Å, b = 4.0592 (9) Å, c = 21.625 (5) Å, β = 99.634 (5)°, V = 1557.2 (6) ų and Z = 4. The molecule has an almost stretched form with a molecular length of 17.505 Å and an imbricated structure known for liquid crystals. The structure contains no direction‐specific intermolecular interactions like aromatic π‐π stacking and C‐H… π(arene) other than two weak C‐H…O hydrogen bonds. Good optical transmittance in the entire visible region of the UV‐Vis spectrum suggests that it is a potential candidate for optoelectronic applications. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Growth and characterization of the nonlinear optical crystal: L‐arginine trifluoroacetate

Single crystal growth of the organic nonlinear optical crystal, L‐arginine trifluoroacetate (L‐Arg·CF₃COOH, abbreviated as LATF) is reported. Low temperature solution growth method is employed for the growth of bulk single crystals. The cell parameters are verified by single crystal diffraction. Fourier transform infrared (FT‐IR) and Fourier transform Raman analysis are used to confirm the presence of various functional groups in the grown crystal. The thermal properties of the grown crystals are studied by thermogravimetric analysis and differential scanning calorinetry analysis (TGA/DSC). Second harmonic generation (SHG) measurement confirms the NLO properties of the grown crystal. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Growth and crystal structure of the layered compound TlGaSe2

The semiconducting compound TlGaSe₂ was grown by solid state reaction technique. The crystal structure of this material was confirmed by single‐crystal X‐ray diffraction. TlGaSe₂ crystallizes in the monoclinic system with space group C2/c (No. 15), Z = 16 and unit cell parameters a = 10.779(2) Å, b = 10.776(1) Å, c = 15.663(5) Å, β = 99.993(6)°. The structural refinement converged to R(F) = 0.0719, R(F²) = 0.0652 and S = 1.17. The structure consists of a three‐dimensional arrangement of distorted TlSe₈ and GaSe₄ polyhedrons. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Synthesis and characterization of 4,4′‐dihydroxy‐α‐methylstilbene crystal

4,4′‐dihydroxy‐α‐methylstilbene (DHAMS) was synthesized by condensation reaction with chloroacetone and phenol in the presence of concentrated sulfuric acid, and has been successfully grown by solution growth technique. This is the first report in the literature on the crystallization of DHAMS and exhibited the birefringent melt (liquid crystal property) of the optical properties. FTIR and FTNMR studies are in accordance with the structure. Good quality crystals were grown by slow evaporation technique by acetone as solvent. A transmission spectrum of the crystal was obtained in the region of 285 nm. The structural and optical properties were studied. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Preparation,single crystal growth and characterization of bis(tetrabutylammonium)bis(4,5‐dithiolato‐1,3‐dithiole‐2‐thione)copper

The preparation and single crystal growth of bis(tetrabutylammonium)bis(4,5‐dithiolato‐1,3‐dithiole‐2‐thione)copper, (I), are described. The energy gap Eg of (I) is about 2.38 eV. The nonlinear optical susceptibility χ⁽³⁾ is about 1.3×10^‐3 esu at 1064 nm. The characterization of (I) has been performed by electronic absorption, infrared and X‐ray powder diffraction spectroscopy. The thermal behavior of (I) has been investigated by means of thermogravimetric analysis (TGA) and differential thermal analysis (DTA) measurements in air. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Growth and characterization of L‐lysine monohydrochloride dihydrate (L‐LMHCl) single crystal

A nonlinear optical crystal of L‐lysine monohydrochloride dihydrate (L‐LMHCl) was grown by slow evaporation solution growth technique using deionised water and mixed solvents of deionised water and ethanol. The functional groups and vibrational frequencies were identified using FTIR and FT‐RAMAN spectra analyses. Also, the presence of hydrogen and carbon atoms in the grown sample was confirmed using proton and carbon NMR spectra analyses. Using TG‐DTA analyses, the decomposition temperature was obtained. Transmittance of the grown crystals was analysed using UV‐visible spectrum. The mechanical strength of the grown crystals was found using Vicker's microhardness tester. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)