Cadmium Oxalate Trihydrate Research Articles

SYNTHESIS AND CHARACTERIZATION IN VITRO ANTIMICROBIAL AND CYTOTOXICITY TESTING OF OXALIC ACID-DERIVED CADMIUM CHELATING AGENTS

Objective: The aim of this study is to investigate the growth, structure, spectral, solubility and biological activity of sodium cadmium oxalate dehydrate (NaCdOx) and cadmium oxalate trihydrate (CdOx) crystals prepared by a single diffusion method in the silica gel medium.Methods: The present crystals were grown using single diffusion methods and tested for XRD, UV absorption (190 to 1100 mm) and solubility (distilled water at 20-29 °C) studies. The antimicrobial efficacy of the grown samples at various concentrations (25, 50, 75 and 100 μg/ml) was studied against Streptococcus, (G+Ve), Pseudomonas aeruginosa (G-Ve) and Candida albicans (antifungal). The cytotoxicity evolution was carried out against human cervical cancer cell line (HeLa) using MTT assays.Results: The existing single crystals were successfully grown by silica gel technique. The solubility of sodium cadmium oxalate dehydrate (NaCdOx) was moderately good in deionized warm water. The FTIR spectral studies confirmed the chelating bands of the present samples and UV spectra showed the better the optical conductivity of as-grown crystals. The complexes showed good antimicrobial activity against all tested microbial strains and they exhibited a decrease in cytotoxicity activity.Conclusion: The gel method was suitable to grow metal complexes of legend crystals. The modification of structural properties of cadmium oxalate trihydrate (CdOx) by sodium doping was much improved the solubility, anticancer, antimicrobial activity and polarization by the high optical conductivity of sodium cadmium oxalate dehydrate (NaCdOx) compound. Hence sodium cadmium oxalate dehydrate (NaCdOx) might be a candidate for biomedical applications.

Heavy Metal Tolerance and Biotransformation of Toxic Metal Compounds by New Isolates of Wood-Rotting Fungi from Thailand

ABSTRACTEighteen isolates of wood-rotting fungi isolated from Thailand were screened for the ability to produce metal-containing crystals from zinc, copper, cadmium and lead salts-amended culture medium. Five isolates (MR40, KYO, WR3, WR4 and WR5) were able to produce mycogenic crystals in 0.5% (w/v) heavy metal compound amended plates. The crystals were further investigated by scanning electron microscopy equipped with energy dispersive X-ray microanalysis (SEM-EDXA) and identified by X-ray powder diffraction (XRPD). The selected fungi were found to be capable of transforming zinc sulfate (ZnSO4·7H2O) into zinc oxalate dihydrate (C2O2Zn·2H2O), copper sulfate (CuSO4·5H2O) into copper oxalate hydrate (C2CuO4·xH2O), cadmium sulfate (3CdSO4·8H2O) into cadmium oxalate trihydrate (C2CdO4·3H2O) and lead nitrate (Pb(NO3)2) into lead oxalate (PbC2O4). Two of the selected strains (Fomitopsis cf. meliae and Ganoderma aff. steyaertanum) have not been previously reported to have heavy metal compound transformation abilities. These results provide further evidence that wood-rotting fungi can remove heavy metals from a metal-amended substrate by precipitation as metal oxalates: wood-rotting fungi could therefore be applied for detoxification of heavy metal pollution.

Diamagnetic and photoabsorption characterisation of gel‐grown cadmium oxalate single crystals

AbstractPerfect single crystals of cadmium oxalate trihydrate have been grown using the slow and controlled reaction between Cd+2 and (C2O4)‐2 ions in agar‐agar gel, resulting in the formation of insoluble product Cd(COO)2.3H2O. The optimum growth parameters have been determined. The variation of magnetic moment of the grown crystals under an applied static magnetic field is studied and the material is found to be diamagnetic. The polarizability is found sensitive to optical band gap. An empirical relation between magnetic susceptibility and electronic polarizability has been established. Optical absorption spectra of the sample recorded in the range 200‐2500 nm reveal transitions involving absorption and emission of phonons. The detailed study supports the existence of allowed direct and indirect allowed gaps in the material. The direct allowed transition prevails in the region of relatively higher photon energy. Some feeble disorder in the crystal is conceived to be present. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Crystal structure and thermal characterization of cadmium oxalate [CdC 2O 4 · 3H 2O] and barium-doped cadmium oxalate [Ba 0.5Cd 0.5(C 2O 4) 2 · 5H 2O] single crystals grown in silica gel

Pure cadmium oxalate trihydrate (COT) and barium added cadmium oxalate (BCO) single crystals were grown by controlled diffusion of Cd 2+ and Ba 2+ ions in silica gel at ambient temperature. A single test tube technique coupled with gel aging conferred maximum size crystals by controlling the nucleation rate. It was found that the pH and age of the gel greatly influenced the crystal quality, their size and transparency. Grown crystals CdC 2O 4 · 3H 2O and Ba 0.5Cd 0.5(C 2O 4) 2 · 5H 2O were characterized by X-ray diffraction, Fourier transform infrared spectroscopy and thermal analysis. Effect of barium dopant on the growth and morphology of cadmium oxalate was studied. Pure cadmium oxalate crystallized in triclinic system and the barium-doped cadmium oxalate crystallized in hexagonal system with massive changes in their unit cell parameters. The infrared spectrum revealed the presence of oxalate ligands and water of hydration in both the pure and barium-doped crystals. Thermal analysis showed that the grown crystals were dehydrated thermally even from lower temperatures and the doped crystals were found more stable.

EPR of VO 2+ in Cd(COO) 2 · 3H 2O single crystal: Superhyperfine interaction with ligand protons

X-band electron paramagnetic resonance (EPR) studies of VO 2+ ions have been carried out in a cadmium oxalate trihydrate single crystal. The EPR spectra, recorded at 295, 80, 42, 19 and 4.2 K, are indicative of a single VO 2+ site in the unit cell. Each vanadyl hyperfine line is characterized by an anisotropic triplet superhyperfine (SHF) splitting, with the intensity ratios 1:2:1; maximum separation of the SHF splitting is observed when the orientation of the external magnetic field is along the Cd-H 2O(II) direction. The principal values, and the direction cosines of the principal axes of the g̃ 2 and à 2 tensors are evaluated from a simultaneous fitting of the EPR line positions, observed for several orientations of the external magnetic field, using a rigorous least-squares-fitting program, suitable for electron-nuclear spin-coupled systems. An impurity model of the vanadyl ion, substituting for the divalent cadmium ion, is proposed. The orientation of the V 4+-O 2- bond has been estimated to be close to the Cd-H 2O(I) direction. The SHF structure is explained to be due to the interaction of the unpaired electron of the VO 2+ ion with the two protons of its nearest-neighbor water molecule H 2O(II); the principal values and the orientations of the principal axes of the SHF interaction tensor have been estimated.

Hyperfine and nuclear quadrupole interactions in copper-doped cadmium oxalate trihydrate single crystals

Electron spin resonance experiments on Cu 2+ doped in a single crystal of cadmium oxalate trihydrate grown by a slow diffusion technique have been carried out at 77 K. The major features of the ESR spectra can be attributed to divalent copper (3 d 9) in substitutional Cd 2+ sites. Information has been gained about the hyperfine and quadrupole interactions concerning the ion. The spin-Hamiltonian parameters in the S = 1 2 , I = 3 2 manifold are: g x = 2.0211; g y = 2.2249; g z = 2.4536; A x = +84.5 × 10 −4 cm −1; A y = +16.8 × 10 −4 cm −1; A z = −40.8 × 10 × −4cm −1 ; P x = −7.4 × 10 −4 cm −1; P y = −0.4 × 10 −4 cm −1; and P z = +7.8 × 10 −4 cm −1. An evaluation of the asymmetry and quadrupole coupling parameters revealed that the ground state of the guest ion in Cd(COO) 2 · 3H 2O is 0.97| x 2 − y 2 > +0.24 |3 z 2 − r 2 >.

EPR of Mn 2+ in Cd(COO) 2· 3H 2O single crystals

The electron paramagnetic resonance spectrum of Mn 2+ has been investigated in cadmium oxalate trihydrate single crystals at room temperature. The spectrum, recorded in the X-band, consists of a set of lines all of which correspond to a single type of environment. None of the principal axes coincides with any crystallographic axis. The spectrum is satisfactorily described by a spin Hamiltonian with a rhombic crystalline electric field. The separations of the forbidden doublets (Δ m = ± 1) in different electronic transitions have been calculated and compared with the observed doublet separations.

Indentation study of cadmium oxalate trihydrate single crystals

Vickers microhardness indentation studies have been made on the as-grown (¯2¯21), (110) and (001) planes, and on the only cleavage plane (1¯10) of gel-grown cadmium oxalate trihydrate single crystals. The material chipping off and slip lines observed around indentation figures have been discussed. The anisotropy in microhardness of the crystals is indicated.

Kinetics of etching and dissolution of gel-grown CdC2O4�3H2O crystals

The kinetics of etching and dissolution of cadmium oxalate trihydrate single crystals in selective etchants such as 1 M HCl, 1 M HNO3, 10% chromic acid, 4M NH4Cl, 4M CdCl2 and 4 M NH4Cl-1 M HCl solutions are studied. Contrary to a previous report on semiconductor etching, in the present investigation the activation energy of etching in solvents having a reaction-rate controlled mechanism of dissolution was lower than in those having a diffusion-rate controlled dissolution mechanism. Three 3-component etch systems, i.e., HCl-NH4Cl-H2O, HCl-CdCl2-H2O, and NH4Cl-CdCl2-H2O, are employed and constant etch rate contours are plotted which enable the part played by each component in association with the other components in the system to be understood.

Etching and Dissolution Mechanism of Cadmium Oxalate Trihydrate Crystals

AbstractDislocation etching and dissolution of gel‐grown cadmium oxalate trihydrate crystals are carried out using different etchants. The study revealed the existence of dislocation network in the body of the crystal and shallow dislocation loops in the substructure. Faster dissolution of the crystal at elevated temperatures revealed that the rate of dissolution in the initial part of the dissolution time is much lesser, which increases fast to attain a steady value. This observation is related to the available specific surface area of the crystal.

The kinetics of crystallization and dissolution of barium oxalate dihydrate and cadmium oxalate trihydrate

The kinetics of crystallization and dissolution of barium oxalate dihydrate and cadmium oxalate trihydrate have been studied at 25°C by following the changes in conductivity when supersaturated or subsaturated solutions are inoculated with seed crystals. In additive-free solutions, the growth of barium oxalate dihydrate seed crystals follows a rate law second order with respect to supersaturation, and a surface-controlled reaction is proposed. The same kinetic equation may be used to interpret the growth of this salt from supersaturated solutions containing a variety of phosphonate additives. However in these experiments the reaction is preceded by an initial fast surge in the concentration—time profiles. The rate of growth of cadmium oxalate trihydrate crystals varies linearly with supersaturation and this can be explained in terms of a surface diffusion model for growth. The dissolutions of both barium oxalate dihydrate and cadmium oxalate trihydrate follows a rate law in which the rate of reaction is proportional to the undersaturation and evidence is presented for a liquid transport rate-determining step for the dissolution reactions. Although both the crystallization and dissolution of cadmium oxalate trihydrate follow similar first order kinetic equations the appreciable differences in the values of the rate constants suggest that they are not reciprocal processes.