The stability of the chloro complexes of magnesium and of the alkaline earth metals at elevated temperatures

1975 ◽  
Vol 40 (7) ◽  
pp. 2020-2024 ◽  
Author(s):  
L. Šůcha ◽  
J. Čadek ◽  
K. Hrábek ◽  
J. Veselý
Keyword(s):  
Alkaline Earth ◽  
Elevated Temperatures ◽  
Alkaline Earth Metals ◽  
Chloro Complexes ◽  
The Stability

Athermochemical Investigation of the La-Sr-Cu-O System

1989 ◽  
Vol 169 ◽  
Author(s):  
Joseph Bularzik ◽  
Alexandra Navrotsky ◽  
Bruce Scott ◽  
Joe Bringley ◽  
Steve Trail
Keyword(s):  
High Temperature ◽  
Alkaline Earth ◽  
High Temperature Superconductors ◽  
Solution Calorimetry ◽  
Alkaline Earth Metals ◽  
Heats Of Formation ◽  
High Temperature Solution ◽  
Calorimetric Measurements ◽  
Temperature Solution ◽  
The Stability

AbstractThe perovskite related La2‐xMxCuO4‐y oxides substituted with alkaline earth metals were one of the first classes of high temperature superconductors discovered. Determining the thermodynamic properties is important to understand the stability and superconducting mechanism of these structures. High temperature solution calorimetry, using a molten lead borate solvent, has been performed on La2CuO4 and the related Sr substituted oxides. Calorimetric measurements on CuO, La2O3 and SrCO3 yield heats of formation. A change in the trend of the heats of formation appears at Sr content 0.1, the reported orthorhombic to tetragonal transition, the onset of superconductivity and loss of oxygen.

scholarly journals The Role of Calcium and Strontium as the Most Dominant Elements during Combinations of Different Alkaline Earth Metals in the Synthesis of Crystalline Silica-Carbonate Biomorphs

Crystals ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 381 ◽  
Author(s):  
Mayra Cuéllar-Cruz ◽  
Abel Moreno
Keyword(s):  
Alkaline Earth ◽  
Chemical Elements ◽  
Living Organism ◽  
Life Forms ◽  
Point Of View ◽  
Alkaline Earth Metals ◽  
Evolution Of Life ◽  
Living Organisms ◽  
The Stability

The origin of life from the chemical point of view is an intriguing and fascinating topic, and is of continuous interest. Currently, the chemical elements that are part of the different cellular types from microorganisms to higher organisms have been described. However, although science has advanced in this context, it has not been elucidated yet which were the first chemical elements that gave origin to the first primitive cells, nor how evolution eliminated or incorporated other chemical elements to give origin to other types of cells through evolution. Calcium, barium, and strontium silica-carbonates have been obtained in vitro and named biomorphs, because they mimic living organism structures. Therefore, it is considered that these forms can resemble the first structures that were part of primitive organisms. Hence, the objective of this work was to synthesize biomorphs starting with different mixtures of alkaline earth metals—beryllium (Be2+), magnesium (Mg2+), calcium (Ca2+), barium (Ba2+), and strontium (Sr2+)—in the presence of nucleic acids, RNA and genomic DNA (gDNA). Our results allow us to infer that the stability of calcium followed by strontium had played an important role in the evolution of life since the Precambrian era until our current age. In this way, the presence of these two chemical elements as well as silica (in the primitive life) and some organic molecules give origin to a great variety of life forms, in which calcium is the most common dominating element in many living organisms as we know nowadays.

scholarly journals Effects of Modifying Acidity and Reducibility on the Activity of NaY Zeolite in the Oxidative Dehydrogenation of n-Octane

Catalysts ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 363 ◽  
Author(s):  
Siyabonga S. Ndlela ◽  
Holger B. Friedrich ◽  
Mduduzi N. Cele
Keyword(s):  
Oxidative Dehydrogenation ◽  
Alkaline Earth ◽  
Earth Metal ◽  
Acid Sites ◽  
Alkaline Earth Metals ◽  
Alkaline Earth Metal ◽  
Ionic Exchange ◽  
Nay Zeolite ◽  
The Stability

Non-coking stable alkaline earth metal (M = Mg, Sr, and Ba) modified Ga-NaY catalysts were prepared by ionic-exchange and tested in oxidative dehydrogenation (ODH) of n-octane using air as the source of oxygen. The role of the alkaline earth metals in NaY was to poison the acid sites while enhancing the basic sites responsible for ODH. The exception was the calcium modified NaY, which was more acidic than the parent NaY, coking and unstable under the ODH conditions used in this study. The role of gallium was to enhance the dehydrogenation pathway and improve the stability of NaY. The sequence of increasing selectivity to octenes followed the order: CaGa-NaY < Ga-NaY< MgGa-NaY < SrGa-NaY < BaGa-NaY. The highest octene selectivity obtained was 37% at iso-conversion of 6 ± 1% when BaGa-NaY was used at a temperature of 450 °C. The activity of the catalysts was directly proportional to the reducibility of the catalysts, which is in agreement with expectations.

Static second hyperpolarizability of Λ shaped alkaline earth metal complexes

2014 ◽  
Vol 13 (05) ◽  
pp. 1450039 ◽  
Author(s):  
Kaushik Hatua ◽  
Prasanta K. Nandi
Keyword(s):  
Metal Complexes ◽  
Alkaline Earth ◽  
Theoretical Study ◽  
Transition Energy ◽  
Earth Metal ◽  
Alkaline Earth Metals ◽  
Basis Set ◽  
Alkaline Earth Metal ◽  
Second Hyperpolarizability ◽  
The Stability

A number of Λ shaped complexes of alkaline earth metals Be , Mg and Ca with varying terminal groups have been considered for the theoretical study of their second hyperpolarizability. The chosen complexes are found to be sufficiently stable and for a chosen ligand the stability decreases in the order: Be -complex > Ca -complex > Mg -complex. The calculated results of second hyperpolarizability obtained at different DFT functionals for the 6-311++G(d,p) basis set are found to be fairly consistent. The Λ shaped ligands upon complex formation with metals lead to strong enhancement of second hyperpolarizability. The highest magnitude of cubic polarizability has been predicted for the metal complex having > C ( C 2 H 5)2 group. For a chosen ligand, the magnitude of second hyperpolarizability increases in the order Be -complex < Mg -complex < Ca -complex which is the order of increasing size and electropositive character of the metal. The variation of second hyperpolarizability among the investigated metal complexes has been explained in terms of the transition energy and transition moment associated with the most intense electronic transition.

Impact of Alkaline Earth Metal Doping on the Stability of Perovskite Solar Cells

2019 ◽  
Author(s):  
Nga Phung ◽  
Hans Köbler ◽  
Diego Di Girolamo ◽  
Thi Tuyen Ngo ◽  
Gabrielle Sousa e Silva ◽  
...  
Keyword(s):  
Solar Cells ◽  
Alkaline Earth ◽  
Perovskite Solar Cells ◽  
Earth Metal ◽  
Alkaline Earth Metal ◽  
Metal Doping ◽  
The Stability
Sign in / Sign up

Export Citation Format

Share Document