scholarly journals Thermodynamic Stability Areas of Polyvanadates of Alkaline Earth Metals

2019 ◽  
Vol 2019 ◽  
pp. 1-6 ◽  
Author(s):  
Igor Povar ◽  
Inga Zinicovscaia ◽  
Oxana Spinu ◽  
Boris Pintilie
Keyword(s):  
Thermodynamic Stability ◽  
Metal Ion ◽  
Alkaline Earth ◽  
Heterogeneous Systems ◽  
Earth Metal ◽  
Thermodynamic Characteristics ◽  
Alkaline Earth Metals ◽  
Alkaline Earth Metal ◽  
Solution Ph ◽  
Alkaline Earth Element

A thermodynamic method of the global Gibbs energy variation calculation for describing heterogeneous equilibria of transformations of calcium, strontium, and barium polyvanadates, that occur in systems MeO-V2O5-H2O, where Me is the alkaline earth element, has been developed and used. Its quintessence consists in the thermodynamic analysis of the real conditions of various processes on the basis of their total thermodynamic characteristics. On the basis of the selected thermodynamic data for involved species, the thermodynamic stability areas of solid polyvanadates towards the solution pH and vanadium and alkaline earth metal ion concentrations in heterogeneous mixtures have been established, taking into account the complex formation reactions in multicomponent heterogeneous systems. The existing experimental data confirm the results on the thermodynamic stability of polyvanadates obtained in this paper.

Structure and bonding in N -methylacetamide complexes of alkali and alkaline earth metals

1981 ◽  
Vol 375 (1760) ◽  
pp. 127-153 ◽  
Keyword(s):  
Metal Ion ◽  
Alkaline Earth ◽  
Bond Distance ◽  
Lone Pair ◽  
Earth Metal ◽  
Carbonyl Oxygen ◽  
Alkaline Earth Metals ◽  
Alkaline Earth Metal ◽  
Ionic Potential ◽  
Out Of Plane

A detailed crystallographic investigation of N -methylacetamide com­plexes of Li, Na, K, Mg and Ca has been made in view of its importance in the coordination chemistry and biochemistry of alkali and alkaline earth metals. The metal ions bind to the amide oxygen causing an increase in the carbonyl distance and a proportionate decrease in the central C—N bond distance. The decrease in the central C—N distance is accompanied by an increase in the distance of the adjacent C—C bond and a decrease in the adjacent C—N bond distance. The metal ion generally deviates from the direction of the lone pair of the carbonyl oxygen and also from the plane of the peptide, the out-of-plane deviation varying with the ionic potential of the cation. The metal-oxygen distance in alkali and alkaline earth metal complexes of a given co­ordination number also varies with the ionic potential of the cation, as does the strength of binding of the cations to the amide. The amide molecules are essentially planar in these complexes, as expected from the increased bond order of the central C—N bond. The NH bonds of the amide are generally hydrogen bonded to anions. The structures of the amide complexes are compared with those of other oxygen donor complexes of alkali and alkaline earth metals. The structural study described here also provides a basis for the interpretation of results from spectroscopic and theoretical investigations of the interaction of alkali and alkaline earth metal cations with amides.

scholarly journals Влияние орбитального упорядочения на спектры магнитного резонанса в зарядово-упорядоченных и фрустрированных манганитах

2019 ◽  
Vol 61 (5) ◽  
pp. 841
Author(s):  
Л.Э. Гончарь
Keyword(s):  
Metal Ion ◽  
Alkaline Earth ◽  
Theoretical Study ◽  
Earth Metal ◽  
Exchange Interactions ◽  
Alkaline Earth Metal ◽  
Antiferromagnetic Resonance ◽  
Rare Earth Ion ◽  
Magnetic Structures ◽  
Low Dimensional

A theoretical study of the interrelation of the crystal structure, charge, orbital, and magnetic subsystems in R1–xAxMnO3 charge-ordered manganites has been carried out (where R3+ is the rare earth ion, A2+ is the alkaline earth metal ion, x = 0.5, 2/3). The model of orbital-dependent exchange interactions and single-ion anisotropy is used. The presence of quasi-low-dimensional magnetic structures is exhibited. The spin waves spectra and antiferromagnetic resonance spectra are calculated.

THERMODYNAMICS OF ALKALI AND ALKALINE EARTH METAL ION - EXCHANGE ON CERIUM(IV) HYDROGEN PHOSPHATE

1995 ◽  
Vol 13 (6) ◽  
pp. 1145-1158 ◽  
Author(s):  
H. Hayashi ◽  
T. Iwasaki ◽  
T. Nagase ◽  
Y. Onodera ◽  
K. Torii
Keyword(s):  
Ion Exchange ◽  
Metal Ion ◽  
Alkaline Earth ◽  
Earth Metal ◽  
Alkaline Earth Metal ◽  
Hydrogen Phosphate ◽  
Metal Ion Exchange
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