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A series of l-amino acids, isoleucine, valine, glutamine, methionine, arginine, cystine and aspargine are employed to form picrates with picric acid (1:1). A comparison of cell parameters reveals that expected picrates are formed only in the case of l-valine and l-isoleucine. l-Isoleucinium picrate (LIP), a new nonlinear optical material was grown from aqueous medium by the slow evaporation of equimolar mixture of l-isoleucine and picric acid. The structure of the grown crystal as determined by single crystal XRD diffraction analysis reveals that it belongs to the monoclinic system with space group P21 and the cell parameter values are, a=9.970(3)Å; b=6.425(2)Å; c=12.871(4)Å; β=109.54(3)°; V=770.0(4)ų; Z=2. The presence of functional groups in the LIP is confirmed by FT-IR vibrational patterns and the good crystallinity indicated by powder X-ray diffraction method. The relative second harmonic generation (SHG) efficiency measurements reveal that the LIP is a highly efficient nonlinear optical (NLO) material having an activity 16 times as that of the reference material potassium dihydrogen phosphate. The optical transparency has been studied using UV-vis spectrophotometer and the absorption is minimum in the visible region. Thermogravimetric and differential thermal analyses reveal the purity of the sample and no decomposition is observed up to the melting point. [ABSTRACT FROM AUTHOR]

Single crystals of zinc cadmium thiourea complex Zn0.625Cd1.375(CS(NH2)2)9.4(SO4) (ZCTS) are grown by slow evaporation of aqueous solution containing zinc sulfate, cadmium sulfate and thiourea in the ratio 1:1:6. Crystal composition as determined by single crystal X-ray diffraction analysis reveals that it belongs to the monoclinic system with space group P21 and cell parameters are a=13.263(5)Å, b=11.886(5)Å, c=27.215(5)Å, α=γ=90.000(5)°, β=96.586(5)°, V=4262(3)Å3 and Z=2. The presence of zinc and cadmium in the final product is further confirmed by inductively coupled plasma (ICP), atomic absorption spectroscopy (AAS) and energy dispersive X-ray spectroscopy (EDS). The vibrational patterns in FT-IR are used for identifying the material and the thermal analysis by TG/DTA indicates the stability of the mixed crystal. The surface morphology changes of the mixed crystal are studied by scanning electron microscopy (SEM). High transmittance in the visible region is observed with a lower optical cut-off at ∼260nm. The change in intensity patterns in XRD profiles indicates lattice distortion. The relative second harmonic generation (SHG) efficiency measurements reveal that the mixed crystal has a superior activity than that of tris(thiourea)zinc(II) sulfate (ZTS). [ABSTRACT FROM AUTHOR]

Abstract: Potassium sodium phthalate monohydrate (K0.78Na1.22[C6H4(COO)2]·H2O) single crystals have been grown from an aqueous solution of potassium hydrogen phthalate enriched with equimolar concentration sodium hydroxide at room temperature. Single crystal XRD analysis reveals that the mixed crystal belongs to the trigonal system with space group P3–1c and the cell parameters are, a=16.7228(2) Å, b=16.7228(2) Å, c=18.2742(5) Å, α=β=90°, γ=120°, υ=4425.75(14) Å3 and Z=12. The partial substitution of cation results in defect centers which influence the physical properties. The co-existence of potassium and sodium ions in the crystal is further confirmed by inductively coupled plasma, atomic absorption spectroscopy and energy dispersive X-ray spectroscopy. The vibrational patterns in FT-IR are used for identifying the material and the thermal study by thermogravimetry/differential thermal analysis indicates the stability. [Copyright &y& Elsevier]

Abstract: Potassium sodium ammonium dihydrogenphosphate K0.23Na0.23(NH4)0.54H2PO4 (KSADP), a new mixed crystal has been grown in aqueous medium by the slow evaporation of equimolar mixture of ammonium dihydrogenphosphate (ADP), potassium dihydrogenphosphate (KDP) and sodium dihydrogenphosphate (SDP). Crystal composition as determined by single crystal X-ray diffraction analysis reveals that it belongs to the tetragonal system with noncentrosymmetric space group I-42d and it is structurally similar to ADP with cell parameter values, a=7.4794(4)Å; b=7.4794(4)Å; c=7.2974(11)Å; υ=408.23(7)Å3; z=4. The presence of sodium and potassium in ADP matrix was confirmed by inductively coupled plasma emission spectrometry and energy dispersive X-ray spectroscopy. The partial cationic substitution results in defect centers influencing the physical properties. Slight shifts in vibrational patterns could be attributed to strains in the lattice. Refinement of structure by single crystal XRD analysis reveals that potassium, sodium and ammonium coexist in the mixed crystal. The surface morphology of the as-grown specimen, which is changed as a result of cationic incorporation, was studied by scanning electron microscopy. The relative second harmonic generation (SHG) efficiency measurements revealed that the mixed crystal has a superior NLO activity than ADP. [Copyright &y& Elsevier]

Abstract: Mixed crystals Zn x Mg(1−x)(NH4)2(SO4)2·6H2O of the two well-known Tutton''s salts Zn(NH4)2(SO4)2·6H2O and Mg(NH4)2(SO4)2·6H2O were grown with varying molar proportions (x=0.10–0.90) by slow evaporation solution growth technique. The mixed crystal Zn0.54Mg0.46(NH4)2(SO4)2·6H2O is crystallizing in monoclinic system with space group P21/c and cell parameters a=6.2217(4)Å, b=12.5343(7)Å, c=9.2557(6)Å, β=106.912(3)°. The coexistence of zinc and magnesium ions in the mixed crystal was confirmed by inductively coupled plasma (ICP), atomic absorption spectroscopy (AAS) and energy dispersive X-ray spectroscopy (EDS). Compositional dependence of lattice parameters follows Vegard''s relations. Slight variations are observed in FT-IR and XRD of pure and mixed crystals. Comparison of crystalline perfection as evaluated by high-resolution X-ray diffraction (HRXRD) for mixed crystals of various proportions reveals a reasonably good crystalline perfection for the mixed crystal with nearly equimolar ratio of Zn and Mg. The surface morphology of the mixed crystals changing with composition was studied by scanning electron microscopy (SEM). UV–vis studies reveal that the transparency of the mixed crystals was not much affected. [Copyright &y& Elsevier]

Highlights: [•] Mixed crystal K2Zn0.84Mn0.16(SO4)2⋅6H2O belongs to monoclinic system with P21/c space group. [•] High-resolution XRD reveals the presence of vacancy type defects in the mixed crystal. [•] Co-existence of Zn and Mg in the mixed crystal is confirmed by single crystal XRD, EDS and AAS. [ABSTRACT FROM AUTHOR]

Abstract: Fe3+-doping at ∼10mol% in aqueous medium during crystal growth by slow evaporation solution method in bis(thiourea)zinc(II) chloride (BTZC) leads to form a new compound C2H8Cl2N4S2Zn0.93Fe0.07 (BTZCF) which crystallizes in orthorhombic structure with centrosymmetric space group Pnma though the parent compound BTZC crystallizes in noncentrosymmetric structure with space group Pn21a. The interesting feature observed in this new crystal is that though it crystallizes in centrosymmetric structure, it exhibits positive SHG result (weak signal), quite likely due to possible surface effects or internal stress. The calculated first-order hyperpolarizability is 1.457×10−30 esu which is ∼5.5 times that of urea. Fe3+-doping enhances the transmittance to a significant extent. Comparison of the thermal analysis results by DSC reveals the incorporation of dopant into the crystalline matrix. The high resolution XRD studies reveal that the crystalline quality is improved considerably when the doping level is reached to ∼10mol%. [Copyright &y& Elsevier]