Chanaiporn Danvirutai

Synthesis, characterization and vibrational spectroscopic study of Co, Mg co-doped LiMnPO4

The isostructural olivine-like LiM(II)PO4 compounds [M(II)=Mn, Mn0.9Co0.1, Mn0.8Co0.1Mg0.1] were successfully generated through the solid state reaction from the synthesized NH4M(II)PO4∙H2O precursors. The TG/DTG/DTA, AAS/AES, FTIR and XRD methods were employed to confirm both NH4M(II)PO4∙H2O and LiM(II)PO4 compounds. Their morphologies were studied by SEM method. The shift of two theta angle of XRD to higher values was observed in metal doping compounds, which indicate the formation of the single phase of isodivalent doping of Co(2+) and Mg(2+) ions according to the change in the lattice parameters and cell volumes. Their infrared spectra are reported and discussed with respect to the normal vibrations of NH4(+), PO4(3-), P2O7(4-) and H2O molecules using factor group analysis. The correlation field splitting analysis of PO4(3-) in NH4M(II)PO4∙H2O (orthorhombic system, Pmn2(1), C(2v)(7) and Z=2, [(3×5)-6]×2=18 internal modes) symbolized as T(d)-C(s)-C(2v)(7) suggested the number of vibrational modes to be: Γ(Vib)=A1(6)+A2(3)+B1(6)+B2(3) and A1(6)+A2(3)+B1(3)+B2(6) for zx and yz plane respectively. While, LiM(II)PO4 crystallizes in the orthorhombic system the space group Pnma (D(2h)(16)), Z=4 and the site symmetry of PO4(3-) is C(s). The correlation field splitting of type T(d)-C(s)-D(2h)(16) were reported in relation to [(3×5)-6]×4=36 internal modes for PO4(3-) unit in the structure.

Thermal decomposition kinetics of Mn0.9Co0.1HPO4·3H2O using experimental-model comparative and thermodynamic studies

Simple direct precipitation was used to synthesize the single-phase Mn0.9Co0.1HPO4·3H2O compound. Two thermal decomposition steps were observed corresponding to the dehydration and polycondensation processes, respectively. The pure-phase Mn1.8Co0.2P2O7 compound was obtained as the final decomposition product. The thermogravimetry/differential thermogravimetry/differential thermal analysis, Fourier transform infrared, atomic absorption spectrophotometry, X-ray diffraction and scanning electron microscope techniques were used to characterize the synthesized compounds. The iterative Kissinger–Akahira–Sunose method was carried out to calculate the exact activation energy

A new synthetic route, characterization and vibrational studies of manganese hypophosphite monohydrate at ambient temperature

E_{\alpha }

CCDC 603979: Experimental Crystal Structure Determination

Eα values. The first (overlapping between Regions I and II) and the final steps were confirmed to be single-step kinetic process with unique kinetic triplets. The experimental and model plots were compared to determine the reaction mechanisms. Regions I and II of the first step were found to be 3-D diffusion of spherical symmetry (

Soft solution synthesis, non-isothermal decomposition kinetics and characterization of manganese dihydrogen phosphate dihydrate Mn(H2PO4)2·2H2O and its thermal transformation products

D_{3}

Synthesis, characterization and non-isothermal decomposition kinetics of manganese hypophosphite monohydrate

D3) and cylindrical symmetry (