Polycrystalline samples of dimeric cadmium tartrate, [(Cd,C4H4O6)2H2O)]3H2O [labeled CdT(I)], were studied using impedance measurements and x-ray powder diffraction. The dependence of the real part of the dielectric constant on temperature showed a sharp peak at about 65 °C, revealing a structural phase transition, while the other broad peak in the temperature range (70<T<85 °C) was due to the loss of water molecules. The x-ray powder diffraction patterns at three temperatures (25, 60, and 70 °C) are consistent with three nonequivalent space groups. According to these results, it seems that this compound undergoes two successive phase transitions: P212121→P21→Pnmn, suggesting an intermediate ferroelectric behavior, labeled CdT(II) between a paraelectric CdT(I) and an anhydrous phase, labeled CdT(III).

Structural and dielectric characterization of cadmium tartrate

http://www.biblioteca.uma.es/bbldoc/articulos/16640135.pdf

Structural Characterization of Doped Calcium Tartrate Tetrahydrate

Formation of calcium pyrophosphate dihydrate (CPPD) crystals in soft tissues such as cartilage, meniscus and synovial tissues lead afflictions. The appearance of these crystals in the synovial fluid give rise to acute arthritis attack, which is known as pseudo-gout. The growth of calcium pyrophosphate crystals in gel medium can mimic the growth in a body. In the present study, calcium pyrophosphate tetrahydrate (CPPT) crystals are grown by a single diffusion gel growth technique and characterized by powder XRD, FT-IR spectroscopy, TGA, kinetic and thermodynamic studies of dehydration and dielectric studies. Monoclinic crystals structure, presence of P-O bonds and four water molecules are confirmed from powder XRD, FT-IR and TGA studies, respectively. The dielectric investigation suggests the reduction in dielectric constant with increase in frequency. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Growth and characterization of gel grown calcium pyrophosphate tetrahydrate crystals

Tartrate (Tar2-) was originally employed in this work as a chelating/structure-directing agent for hydrothermal crystallization of ZnWO4, where the decisive roles of Tar2-/Zn2+/WO42- molar ratio, solution pH (7-10), and the use of ethylene glycol (EG) cosolvent in phase/morphology evolution were deciphered in detail. It was unambiguously manifested that Tar2- may remarkably retard the intrinsically preferred [001] growth of ZnWO4, transform 1D nanorods to 0D nanoparticles and then to 2D platelets, and meanwhile induce face-to-face alignment of the platelets to form spheroidal, ellipsoidal and snowflakelike 3D architectures, where the 2D crystallites were revealed to develop via oriented attachment (colattice) of non-(00l) facets. A lower solution pH and excessive WO42- were clearly shown to enhance and offset the effect of Tar2-, which led to ellipsoidal assemblies of substantially larger 2D crystallites and suppressed 2D growth/3D assembly of ZnWO4 crystallites, respectively. With the spheroidal architectures for example, doping ZnWO4 with RE3+ yielded (Zn0.98RE0.02)WO4 phosphors (RE = Sm, Eu, Tb, and Dy, respectively) that show luminescence overlapped from the typical linelike and broad-band (∼350-700 nm) emissions of RE3+ and WO6, respectively. The luminescence color of the sample was found to drift away from the blue corner of the CIE chromaticity diagram with RE3+ doping and to be dependent on the type of RE3+.

Morphology Tailoring of ZnWO4 Crystallites/Architectures and Photoluminescence of the Doped RE3+ Ions (RE = Sm, Eu, Tb, and Dy).

Dielectric and thermal characteristics of gel grown single crystals of ytterbium tartrate trihydrate have been carried out. The dielectric constant has been measured as a function of frequency in the range 2 kHz–1 MHz and temperature range 30–300 °C. The dielectric constant increases with temperature, attains a peak near 215 °C, and then decreases as the temperature exceeds 215 °C. The dielectric anomaly at 215 °C is suggested to be due to phase transition brought about in the material. The dielectric behaviour of the material is correlated with the results on thermal analysis. Thermogravimetric and differential thermal analysis have been used to study the thermal characteristics of the material. The experimental results show that the material is thermally stable up to 200 °C. The decomposition process occurs in two stages until ytterbium oxide is formed at 700 °C. The non-isothermal kinetic parameters e.g., activation energy and the frequency factor have been evaluated for each stage of thermal decomposition by using the integral method, applying the Coats–Redfern approximation.

Dielectric and thermal characteristics of gel grown single crystals of ytterbium tartrate trihydrate

The paper reports on the growth of single crystals of zinc tartrate, by reaction of aqueous solutions of tartaric acid (L +) and zinc chloride in silica gels. The grown crystals have been characterized by X-ray, infrared spectroscopy, qualitative elemental analysis, thermoanalytical techniques, and electromagnetic studies.



En este articulo se describe el crecimiento de monocristales de tatrato de zinc, por reaccion de soluciones acuosas de acido tartarico (L +) y cloruro de zinc en geles de silice. Los cristales crecidos han sido caracterizados por rayos-X, espectroscopia infrarroja, analisis elemental cualitativo, tecnicas termoanaliticas y estudios electromagneticos.

Infrared Spectroscopic, Thermal and Electromagnetic Studies of Zinc Tartrate Single Crystals Grown by the Silica‐Gel Technique

The preparation, characterization (UV/VIS, IR, Mass, 1HNMR, and 13CNMR-DEPT, heteronuclear multiple quantum correlation (HMQC), X-ray diffraction and DSC), measurements of optical second-harmonic generation SGH and dielectric studies of 3-acetamide-4-N-cyclooctylamine-mitrobenzene (ACN), a new organic molecular crystal with potential applications in nonlinear optics are reported.



Se describe la preparacion, caracterizacion (UV/VIS, IR, Mass, 1HNMR and 13CNMR-DEPT, HMQC, difraccion de rayos X y DSC), medidas sobre generacion de segundos armonicos GSA y estudios dielectricos sobre el 3-acetamido-4-N-ciclooctilamino-nitrobenceno (ACN), un nuevo cristal molecular organico con potenciales aplicaciones en optica no lineal.

M. E. Torres

Papers

Infrared Spectroscopic, Thermal and Electromagnetic Studies of Zinc Tartrate Single Crystals Grown by the Silica‐Gel Technique

Preparation and Characterization of 3‐Acetamide‐4‐N‐Cyclooctylamino‐Nitrobenzene Crystals: A New Organic Material for Nonlinear Optics