640-67-5Relevant academic research and scientific papers
Preparation and thermal dehydration of manganese(II) dicarboxylate hydrates
Suzuki, Yukihiko
, p. 155 - 170 (1995)
Manganese(II) dicarboxylate hydrates Mn[OOC(CH2)nCOO] . xH2O have been prepared by the addition of MnCO3 powder or concentrated MnSO4 solution to aqueous solutions of the corresponding dicarboxylic acids. The crystalforms of the precipitated compounds were observed by optical microscopy . The crystals were obtained either as ellipsoidal, short rods or very small uneven particles. The crystals were different from those of the dicarboxylic acids. The dicarboxylates obtained were characterized by X-raydiffraction analysis and IR spectral measurement. The thermal dehydrati ons of the Mn(II) dicarboxylate hydrates were investigated by TG-DTA. The temperatures at which dehydration occured were taken as a measure of the strength of the Mn-OH2 bond, and these were found to vary with increasing number of CH2 groups in the dicarboxylic acid. The kinetic parameters for the dehydration were calculated by employing a computation method. The three-dimensional diffusion model is found to be the best for describing the kinetic results for the main reaction.
Synthesis of micro- and nanosized manganese oxides from hydrated manganese oxalates and products of their chemical modification with ethylene glycol
Gyrdasova,Krasil'nikov,Bazuev
, p. 1035 - 1040 (2009)
The reactions of ethylene glycol with manganese oxalates MnC 2O4 · 2H2O and MnCO 4 · 3H2O on heating in air were studied. At temperature below 100° C, ethylene glycol was found to displace
Thermal and electrical properties of manganese (II) oxalate dihydrate and cadmium (II) oxalate monohydrate
Nikumbh,Athare,Pardeshi
, p. 187 - 192 (1999)
The thermal decomposition of MnC2O4·2H2O and CdC2O4·H2O have been studied by two probe direct current electrical conductivity measurements under the atmospheres of static air, dynamic dry n
Magnetic behavior of MnCo2O4+δ spinel obtained by thermal decomposition of binary oxalates
Bazuev,Korolyov
, p. 2262 - 2268 (2008)
Manganese cobaltites MnCo2O4.62 and MnCo2O4.275 having a spinel structure were studied by measuring magnetization, AC susceptibility and by XANES spectroscopy. These compounds were synthesized by decomposition of the binary oxalate Mn1/3Co2/3C2O4· 2H2O in air at 220 and 500 °C, respectively. It was found that the differences in magnetic characteristics of these cation-deficient spinels are due mainly to variations in the degree of oxidation of manganese. It was shown that the complex oxide MnCo2O4.62 formed right after decomposition of the binary oxalate contains about 5×10-4 mass% metallic cobalt, which determines the dependence of magnetic susceptibility χ on the magnetic field at 300 K. The magnetic transition peculiar to the stoichiometric spinel MnCo2O4 at 183 K decreases to 167.5 K for MnCo2O4.275 and 67.5 K for MnCo2O4.62.
Dehydration reaction of manganese(II) oxalate dihydrate in the solid state: New method in the study of non-isothermal kinetics
Pan,Guan,Feng,Wu,Li
, p. 877 - 884 (1999)
A new method was proposed for determining the most probable mechanism function of a solid phase reaction. According to Coats-Redfern's integral equation Eβ→0 was calculated by extrapolating β to zero using a series of TG curves with different heating rates. Similarly, Eα→0 was calculated according to Ozawa's equation. The most probable mechanism function of the solid phase dehydration of manganese(II) oxalate dihydrate was confirmed to be G(α)=(1-α)1/2 by comparing Eα→0 with Eβ→0.
Structure and magnetic characteristics of an oxalate-bridged U(IV)-Mn(II) three-dimensional network
Moertl, Klaus P.,Sutter, Jean-Pascal,Golhen, Stephane,Ouahab, Lahcene,Kahn, Olivier
, p. 1626 - 1627 (2000)
An oxalate-bridged 3d - 5f compound, K2MnU(C2O4)4 9H2O, is the product of the reaction of K4U(C2O4)4 with a Mn(II) salt. Single-crystal structure analysis shows a three-dimensional network with a diamond-type architecture. The magnetic properties have been examined.
Point defects of tephroite. I: The electrical conductivity of Mn2SiO4
Stueber, Christoph,Laqua, Wolfgang
, p. 197 - 218 (1998)
The electrical conductivity σ of single crystalline Mn2SiO4 (tephroite) grown from the melt, was investigated by impedance spectroscopy between 1101 and 1197°C as function of oxygen activity within the range ～10-16 ≤ ao2 ≤ 0.21 (air). Mn2SiO4 is n-conducting within the low and p-conducting within the high oxygen-activity regime, independent whether the sample are buffered against MnO or MnSiO3. Based on our experimental results we propose a point-defect model the majority defects of which are vacancies in the manganese sublattice V″Mn, Mn3+-ions on Si-lattice sites Mn′Si, holes h' (= Mn'Mn) and electrons e′. Unlike Fe2SiO4 (fayalite), wherein according to thermogravimetric results of Nakamura and Schmalzried [1] associates {Fe'FeFe′Si}x exist, our defect model works without postulating the analogous species {MnMnMn′Si}x to exist in tephroite. We drew this conclusion from the 1/5.5-power law which is followed by our σ-ao2-plots measured on stoichiometric tephroite in the high-ao2, regime, whereas Nakamura and Schmalzried derived an 1/5.0 power law from their measurements in the range of similar oxygen activities on likewise stoichiometric fayalite. The equilibrium constants for formation reactions of the aforementioned defects, which emerged from our experiments were used to depict Kroeger-Vink diagrams ; they describe the dependence of defect concentrations on oxygen activities for both MnO resp. MnSiO3 buffered tephroite. by R. Oldenbourg Verlag, Muenchen 1998.
Luminescence of YPO4:Zr and YPO4:Zr,Mn under vacuum ultraviolet excitation
Kaneyoshi, Masami,Nakazawa, Eiichiro
, p. H80-H83 (2005)
Novel UV and blue phosphors, YPO4:Zr and YPO4:Zr,Mn, respectively, are synthesized and investigated. YPO4:Zr shows the emission about 290 nm assigned to the charge transfer transition of O-Zr. The excitation spectrum of th
Textural and capacitive characteristics of MnO2 nanocrystals derived from a novel solid-reaction route
Yuan, Anbao,Wang, Xiuling,Wang, Yuqin,Hu, Jie
, p. 1021 - 1026 (2009)
Nanostructured manganese dioxide (MnO2) materials were synthesized via a novel room-temperature solid-reaction route starting with Mn(OAc)2·4H2O and (NH4)2C2O4·H2O raw
A comparative study of the magnetic and magnetocaloric effect of polycrystalline Gd0.9Y0.1MnO3 and Gd0.7Y0.3MnO3 compounds: Influence of Y-ions on the magnetic state of GdMnO3
Ahmed, Afsar,Das, I.,Das, Kalipada,Mazumdar, Dipak
, (2022/02/22)
The modification of the magnetic ground state of the GdMnO3 compound has been explored with Y-doping on the Gd-site. The study on the magnetic properties indicates the existence of a weak ferromagnetic phase upon a 10% Y-doped sample. However, the strength of the ferromagnetic interaction becomes feeble in the 30% Y-doped sample. Such modifications of the magnetic ground states are analyzed considering the breaking of correlated weak ferromagnetic chains due to doping of non-magnetic Y-ions. In addition to that, the magnetocaloric effect has also been affected by the doping concentrations of Y-ions. The significant value of magnetic entropy change and relative cooling power of both the studied systems indicate the possible utilization of the materials as efficient magnetic refrigerants at the cryogenic temperature.
