Search

Synthesis of MgC2O4⋅2H2O nano particles was carried out by thermal double decomposition of solutions of oxalic acid dihydrate (C2H2O4⋅2H2O) and Mg(OAc)2⋅4H2O employing CATA-2R microwave reactor. Structural elucidation was carried out by employing X-ray diffraction (XRD), particle size and shape were studied by transmission electron microscopy (TEM) and nature of bonding was investigated by optical absorption and near-infrared (NIR) spectral studies. The powder resulting from this method is pure and possesses distorted rhombic octahedral structure. The synthesized nano rod is 80 nm in diameter and 549 nm in length.

The microwave synthesis of MnC2O4·2H2O nanoparticles was performed through the thermal double decomposition of oxalic acid dihydrate (C2H2O4·2H2O) and Mn(OAc)2·4H2O solutions using a CATA-2R microwave reactor. Structural characterization was performed using X-ray diffraction (XRD), particle size and shape were analyzed using transmission electron microscopy (TEM). The chemical in the structures was investigated using electron paramagnetic resonance (EPR) as well as optical absorption spectra and near-infrared (NIR) spectroscopies. The nanocrystals produced with this method were pure and had a distorted rhombic octahedral structure.

A voglite mineral sample of Volrite Canyon #1 mine, Frey Point, White Canyon Mine District, San Juan County, Utah, USA is used in the present study. An EPR study on powdered sample confirms the presence of Mn(II) and Cu(II). Optical absorption spectral results are due to Cu(II) which is in distorted octahedron. NIR results are indicating the presence of water fundamentals.

pelecypod shell originated from Kolleru lake of Andhra Pradesh is used in the present work. It contains Mn(II) and Fe(III) in traces. The EPR spectrum of the compound is due to Mn(II) which is in three independent sites . The three g values are evaluated with slight differences. The hyperfine component varies from 9.33 mT to 9.49 mT. The zero field splitting parameter is also ranges from 43.8(1) mT to 44.1(1) mT. Using the covalence parameter the number of ligands around metal is estimated as twenty. In EPR spectrum Fe(III) is identified. The optical absorption spectrum is attributed to Mn(II) in octahedral geometry. Further 10 Dq band is attributed to Fe(II) in the optical absorption spectrum. NIR spectral results are due to water fundamentals. Where as IR and Raman spectrum is due to carbonate ion fundamentals.

Leaves of Bhringaraj and Guduchi herb of Kadapa district of Andhra Pradesh, India are dried and powdered. ICP-MS analysis of samples indicates that copper is present in both the samples. An EPR study of guduchi sample also confirms the presence of Fe(III) whereas eclipta alba confirms the presence of Fe(III), Mn(II) and Cu(II) Optical absorption spectrum of guduchi indicates that Cu(II) is present in rhombically distorted octahedral environment. NIR and IR results are due to carbonate fundamentals.

Clinohumite, a humite group mineral, originated from Pamir Mountains, USSR is used in the present work. Optical absorption, electron paramagnetic resonance (EPR), near infrared (NIR) and Mossabauer techniques are used in the characterization of the mineral sample. The optical absorption spectrum indicates that Fe(II) impurity is present in two sites with distorted octahedral structure. NIR results are attributed to water fundamentals. EPR studies on powder sample confirm the presence of Mn(II) in three different sites and also an iron impurity. Mossabauer studies confirm the presence of iron impurity in two different sites.

Apjohnite, a naturally occurring Mn-bearing pseudo-alum from Terlano, Bolzano, Italy has been characterized by EPR, optical, IR and Raman spectroscopy. The optical spectrum exhibits a number of electronic bands around 400 nm due to Mn(II) ion in apjohnite. From EPR studies the parameters derived, g = 2.0 and A = 8.82 mT confirm MnO(H2O)5 distorted octahedra. The presence of iron impurity in the mineral is reflected by a broad band centered around 8400 cm-1 in the NIR spectrum. A complex band profile appears strongly both in IR and Raman spectra with four component bands around 1100 cm-1 due to the reduction of symmetry for sulphate ion in the mineral. A strong pair of IR bands at 1681 and 1619 cm-1 with variable intensity is a proof for the presence of water in two states in the structure of apjohnite.