inorganic chemistry

Priyamstudycentre.com, 2021

Manganese (Mn), chemical element, a greyish-white hard, brittle paramagnetic metal of Group 7 (VIIB) of the periodic table used mainly as an additive to steel. The Swedish chemist Bergmann discovered the presence of magnesium in the black magnesia but fails to isolate it. In chemistry, the element was isolated by another Swedish chemist Johan Gottlieb Gahn and studies by the Swedish chemist Carl Wilhelm Scheele in 1774. At first, the metal was named in Latin word magnesium from the old name pyrolusite but in 1808, the Latin name of manganese changed to manganism to avoid confusion.

Mononuclear, binuclear Ni II and heterobinuclear Zn II Ni II complexes have been derived from lateral macrobicyclic tricompartmental ligands embracing three different donor sets: (i) O 2 N 2 -donor set, derived from ether oxygens and tertiary amine nitrogens; (ii) N 2 O 2 -donor set, derived from tertiary amine nitrogens and phenolic oxygens; (iii) O 2 N 2 -donor set, derived from phenolic oxygens and azomethine nitrogens. Cyclic voltammograms of the mononuclear Ni II complexes showed irreversible one-electron reduction processes in the )1.2 to )1.3 V region and an irreversible oxidation process in the range +0.8 V potential region. The binuclear complexes showed quasireversible two-step single electron reduction processes around the )1.3 and )1.7 V potential regions. The anodic potential region showed an irreversible oxidation process at +1.0 V. The heterobinuclear Zn II Ni II complex showed an irreversible reduction of the Ni II species at )1.55 V. The catalytic hydrolysis towards 4-nitrophenyl phosphate by the mononuclear, binuclear Ni II complexes and the heterobinuclear complex were found to be appreciable. The pseudo-first order rate constant for the catalytic hydrolysis catalyzed by the binuclear and heterobinuclear complexes were found to be higher (9.8 · 10 )4 s )1 ) than that of the corresponding mononuclear complexes (1.3 · 10 )5 s )1 ), which ascertain the requirement of two metal ions in close proximity for the binding of the nucleophilic OH and the phosphate group.

Plant and Soil, 1969

Thermochimica Acta, 2009

In this work the reaction between several manganese oxides and chlorine is investigated. The reaction path for the chlorination of the oxides is established, which involves recrystallization of high valence manganese oxides: Mn 3 O 4 and Mn 2 O 3 during the chlorination of MnO, and Mn 2 O 3 during the chlorination of Mn 3 O 4 and Mn 2 O 3. The starting temperature for the reaction of the oxides is determined by non-isothermal thermogravimetric measurements. Analysis of the samples at different reaction degrees reveals that three simultaneous processes are taking place during the whole reaction: chlorination, volatilization of manganese chloride and recrystallization of manganese oxides. The effect of temperature in the reaction rate is analyzed. The activation energies obtained for the reaction of the three oxides with chlorine, which are in accordance with the vaporization enthalpy of MnCl 2 , suggest that although during the mass loss three processes occur (chlorination, recrystallization and volatilization), volatilization of manganese chloride has a strong influence in the rate observed.

Foundations of Chemistry, 2010

While most chemists agree on what is a metal and what is a non-metal there is a disagreement with respect to what is a metalloid and what is a transition metal. It is believed that this problem can be solved if two new terms are adopted: typical and less typical metals. These new terms will also help reconcile the European Periodic the North American regarding numbering of groups as well as the IUPAC numbering which could be as well abandoned in favour of group names as will be shown in the manuscript.