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Subashini A.,Velammal Institute of Technology | Rajarajan K.,Rajeswari Vedachalam Government Arts College | Sagadevan S.,AMET University
Materials Research Express | Year: 2017

In the present work, bulk size single crystal of tetrakis thiourea potassium bromide [K(N2H4CS)4Br]; (TTPB) has been grown from an aqueous solution using slow evaporation solution growth method. The XRD result proved that the compound crystallize in tetragonal crystal system with space group P41. The FT-IR spectrum of TTPB has clearly identified the functional groups of thiourea in the resulting compound. The TG-DTA and DSC studies have been carried out on the grown sample of TTPB and the results are reported. The etching and scanning electron microscope studies were also carried out to understand the growth pattern and surface morphology of TTPB. The spectral, optical and thermal studies of TTPB are compared with the similar thiourea complex crystal [K(N2H4CS)4I]; (TTPI) and reported. © 2017 IOP Publishing Ltd.


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.


Ramesh V.,Bharathiar University | Shihabuddeen Syed A.,Bharathiar University | Jagannathan K.,SRM University | Rajarajan K.,Rajeswari Vedachalam Government Arts College
Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy | Year: 2013

Single crystal of bis mercury ferric chloride tetra thiocyanate [Hg 2FeCl3(SCN)4; (MFCTC)] was grown from ethanol-water (3:1) mixed solvent using slow evaporation solvent technique (SEST) for the first time. The cell parameters of the grown crystal were confirmed by single crystal XRD. The coordination of transition metal ions with the SCN ligand is well-identified using FT-IR spectral analysis. The chemical composition of MFCTC was confirmed using CHNS elemental test. The ESR spectral profile of MFCTC was recorded from 298 K to 110 K, which strongly suggests the incorporation of Fe3+ ion and its environment with respect to SCN ligand. The HPLC chromatogram of MFCTC highlights the purity of the compound. The UV-Vis-NIR studies revealed the ultra violet cut-off wavelength of MFCTC in ethanol as 338 nm. The dielectric constant and dielectric loss of the sample were studied as a function of frequency and temperature. The TGA-DTA and DSC thermal analysis show that the sample is thermally stable up to 234.31 °C, which is comparatively far better than the thermal stability of Hg 3CdCl2(SCN)6; (171.3 °C) and other metal-organic coordination complex crystals such as CdHg(SCN)4 (198.5 °C), Hg(N2H4CS)4Mn(SCN)4 (199.06 °C) and Hg(N2H4CS)4Zn(SCN) 4 (185 °C). The SHG conversion efficiency of MFCTC is found to be higher than KDP. © 2013 Elsevier B.V. All rights reserved.


PubMed | Rajeswari Vedachalam Government Arts College, Loyola College Autonomous and The New College Autonomous
Type: Journal Article | Journal: Acta crystallographica. Section E, Crystallographic communications | Year: 2015

In the title complex, [Hg(NCS)2(CH4N2S)2], the Hg(II) atom is four-coordinated having an irregular four-coordinate geometry composed of four thione S atoms of two thio-cyanate groups and two thio-urea groups. The S-Hg-S angles are 172.02(9) for the trans-thio-cyanate S atoms and 90.14(5) for the cis-thio-urea S atoms. The mol-ecular structure is stabilized by an intra-molecular N-HS hydrogen bond, which forms an S(6) ring motif. In the crystal, mol-ecules are linked by a number of N-HN and N-HS hydrogen bonds, forming a three-dimensional framework. The first report of the crystal structure of this compound appeared in 1966 [Korczynski (1966 ). Rocz. Chem. 40, 547-569] with an extremely high R factor of 17.2%, and no mention of how the data were collected.


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.


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

The title compound, (NH4)2[Zn(NCS)4]·2C12H24O6·H2O, the result of the reaction of ammonium thiocyanate, 18-crown-6 and zinc(II) chloride in aqueous solution, exhibits an unusual supramolecular structure. The Zn atom, two of the thiocyanate chains and a water molecule, disordered over two positions, lie on a mirror plane. The macrocycle adopts a conformation with approximate D 3d symmetry. The ammonium molecules are contained within the bowl of the macrocycle via extensive N - H⋯O hydrogen bonds and the complex molecules are linked via N - H⋯S hydrogen bonds, forming chains along the c-axis direction. The macrocycle is disordered over two positions [refined occupancy ratio = 0.666 (8):0.334 (8)]. The S atoms of two isothiocyanate ligands are disordered within and about the mirror plane.


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.


Ramesh V.,Bharathiyar University | Rajarajan K.,Rajeswari Vedachalam Government Arts College | Kumar K.S.,Bharathiyar University | Subashini A.,Bharathiyar University | Nizammohideen M.,New College Autonomous
Acta Crystallographica Section E: Structure Reports Online | Year: 2012

In the title compound, {(NH 4)[Cd(NCS) 3]·C 12H 24O 6} n, the Cd 2+ ion, the ammonium cation, one of the SCN - ligands and the macrocycle are located on mirror planes. The thiocyanate anions act as bridging ligands between the Cd II ions, leading to a polymeric chain arrangement extending along [001] around a twofold screw axis. The ammonium ions are contained within the bowl of the macrocycle via extensive N - H⋯O hydrogen bonding.


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.


Rajarajan K.,Rajeswari Vedachalam Government Arts College | Sendil Kumar K.,Bharathiar University
Journal of Thermal Analysis and Calorimetry | Year: 2013

Good quality needle shaped (14 × 3 × 3 mm3) single crystals of ammonium mercury chloride thiocyanate (NH4[HgCl 2(SCN)]; AMCTC) were grown using slow solvent evaporation method for the first time. The incorporation of thiocyanate ligand is confirmed by the strong and highly intense FT-IR band observed at 2112.0 cm-1, which corresponds to the stretching frequency vibration of CN. The signal at about 120 ppm of FT-NMR spectrum is a strong evidence, which in turn supports the binding of thiocyanate in the resulting compound of AMCTC. Further, the sample was also subjected to UV-Vis-NIR and TG-DTA and DSC studies to understand the range of optical transparency and thermal stability of the sample, respectively. The melting point of AMCTC is found to be 151.7 C. The powder second harmonic generation efficiency of the sample is superior to potassium dihydrogen phosphate. © 2012 Akadémiai Kiadó, Budapest, Hungary.

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