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Shihabuddeen Syed A.,Bharathiar University | Rajarajan K.,Rajeswari Vedachalam Government Arts College | Nizammohideen M.,New College Autonomous
Acta Crystallographica Section E: Structure Reports Online | Year: 2013

In the title salt, [Hg(NCS)(CH4N2S)3]Cl, the Hg2+ ion is coordinated in a severely distorted tetrahedral manner by three thiourea groups and one thiocyanate anion through their S atoms. The S - Hg - S angles vary widely from 87.39 (5) to 128.02 (4)°. Weak intramolecular N - H⋯S hydrogen bonds are observed, which form S(6) ring motifs. In the crystal, the ions are linked by N - H⋯N and weak N - H⋯Cl interactions, generating a three-dimensional network. © Shihabuddeen Syed et al. 2013. Source

Rajarajan K.,Rajeswari Vedachalam Government Arts College | Pugazhenthi A.,Bharathiyar University | Nizammohideen M.,New College Autonomous
Acta Crystallographica Section E: Structure Reports Online | Year: 2013

The reaction of CdCl2, 18-crown-6 and KI in water yields the title coordination polymer, [{K(C12H24O6)}2Cd2I6] n. The potassium ion lies approximately in the plane of the crown ether, coordinated by all six crown ether O atoms and also by an iodide anion bound to a cadmium atom. A C atom of the crown ether is disordered over two positions with site occupancies of 0.77 (2) and 0.23 (2). Two K(18-crown-6)+ units are linked by inversion symmetry, forming a [bis(μ2-18-crown-6) dipottasium] system with approximately square-planar K2O2 units. Inversion symmetry also generates the Cd2I6 fragment and the polymeric system is extended along the c axis by the formation of K - I - Cd bridges. Source

Ramesh V.,Bharathiar University | Rajarajan K.,Rajeswari Vedachalam Government Arts College
Applied Physics B: Lasers and Optics | Year: 2013

It is reported here, for the first time, that high-quality bulk size (18 × 5 × 4 mm3) single crystals of a new nonlinear optical crystal, [(NH4)[Cd(NCS)3]C12H 24O6] [Ammonium (18-crown-6-ether) Cadmium(II) tri-thiocyanate; ACCTC], have been grown from aqueous solution via slow evaporation technique. Solubility of ACCTC has been determined for various temperatures. The grown crystals were characterized by single crystal X-ray diffraction, FT-IR, FT-Raman, and UV-Vis-NIR studies. ACCTC crystallizes in orthorhombic system with cell parameters a = 14.7568 Ç, b = 15.4378 Ç, and c = 10.6383 Ç with space group Cmc21. The optical second-harmonic generation effect has been measured by using the Kurtz powder technique and is found to be 2 times higher than that of KDP (KH 2PO4). The sample possesses wide optical transparency range from 200 to 2,500 nm. The TG-DSC thermal analysis revealed that the sample is thermally stable up to 237.92 C, which is comparatively far better than the thermal stability of [(18C6)Li][Cd(SCN)3]; CLTC (170 C). © 2013 Springer-Verlag Berlin Heidelberg. Source

Esther Jeyanthi C.,Bharathiar University | Esther Jeyanthi C.,Panimalar Engineering College | Siddheswaran R.,University of West Bohemia | Kumar P.,Academia Sinica, Taiwan | And 2 more authors.
Ceramics International | Year: 2014

In the present article, a simple and cost-effective citrate nitrate auto-combustion method was used for the high-yield synthesis of rare-earth (RE) ions doped ceria (RELa,Sc,Yb:CeO2) in the form of Ce 0.9La0.1O1.95, Ce0.9Sc 0.1O1.95 and Ce0.9Yb0.1O 1.95 nanoparticles. The as-synthesized powders were calcined at 700 °C and converted into cylindrical compacts by sintering at 1200 °C. The X-ray diffraction study confirmed that all the combinations crystallized as the cubic fluorite structure of pure ceria. The microstructure of the synthesized powders and sintered bodies was examined by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The particles size of the rare-earth (RE) doped ceria was found to be in the range from 20 to 50 nm. The optical absorption by functional molecules, impurities and oxygen vacancies was analyzed by FTIR and Raman spectroscopic studies. From the FTIR spectrum, the absorption peak found at 1070 and 550 cm-1 was attributed to the vibrations of metal-oxygen bonds. The characteristic Raman peak was observed at 460 cm -1 and weak absorptions of oxygen vacancies were observed in the region 460-600 cm-1. The micro-hardness values of the sintered compacts were measured using Vickers indentation experiments. The hardness values of the RELa,Sc,Yb:CeO2 were in the range from 4700 to 7200 MPa. © 2014 Elsevier Ltd and Techna Group S.r.l. Source

Rajarajan K.,Rajeswari Vedachalam Government Arts College | Sendil Kumar K.,Bharathiar University | Ramesh V.,Bharathiar University | Shihabuddeen V.,Bharathiar University | Murugavel S.,Vellore Institute of Technology
Acta Crystallographica Section E: Structure Reports Online | Year: 2012

In the title polymeric complex, [Co(NCS)2{SC(NH 2)2}2] n , the asymmetric unit comprises a CoII ion, which is situated on an inversion centre, an N-bound thio-cyanate anion and a 2-bridging thio-urea mol-ecule. The CoII atom is coordinated in a distorted octa-hedral fashion within an N2S4 donor set. The bridging thio-urea ligands link CoII ions into a polymeric chain extending along [100]. The mol-ecular conformation is stabilized by intra-molecular N-H⋯N hydrogen bonds, which generate S(6) ring motifs. The crystal packing is stabilized by N-H⋯S inter-actions, which connect the chains into a three-dimensional architecture. Source

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