variable valency
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2021 ◽  
Vol 75 (12) ◽  
pp. 1052-1053
Author(s):  
Edwin C. Constable

When he introduced the concept of atomic weights at the beginning of the 19th Century CE, John Dalton assumed that water had the formula HO. This assumption resulted in a half century of confusion – partly because on a scale of H = 1, he defined the atomic weights O = 8 and C = 6, and partly because elements that could exhibit variable valency appeared to possess different atomic (or rather equivalent) weights. The correction of the formula of water, together with the recognition of the diatomic nature of the gases hydrogen and oxygen, were formalized following the Karlsruhe congress of 1861 and allowed the establishment of the 'modern' and consistent atomic weights.


2021 ◽  
Vol 899 ◽  
pp. 215-219
Author(s):  
Rinat Mukhamedzyanov ◽  
Zufar Muzipov ◽  
The Son Pham ◽  
Elina Vasilyeva ◽  
Raisa Akhmedyanova

The process of oxidation of hydrocarbon with oxygen proceeds with formation of the corresponding hydroperoxide as the primary product [1,2]. A catalyst is the most important factor that influences on the direction of flow of the oxidation reaction. Catalysts based on metals of variable valency, and their derivatives are the most active in reactions of oxidation of hydrocarbon [3].


Author(s):  
Maria Kasatenkova ◽  
Maria Kasatenkova ◽  
Nicolay Kasimov ◽  
Nicolay Kasimov ◽  
Mihail Lychagin ◽  
...  

The last 1978-1995 transgression of the Caspian Sea caused the development of marsh-lagoon system along the Western Caspian seashore. Due to salt marshes are very vulnerable to sea-level fluctuations, complex and dynamic system, they may be considered as a regional model of rapid environmental transformation. Changing conditions of migration in the soils of marsh-lagoon landscapes during the sea-level rise influenced on the migration of elements of variable valency, primarily Fe and Mn, but also Zn, Cu, Pb, Ni, Co, leading to their mobilization in slightly alkaline and neutral reducing conditions and subsequent deposition on the geochemical barriers. That led to the emergence of landscape-geochemical anomalies of Fe and heavy metals in the soils of salt marshes with a characteristic time of formation of any persistent anomalies during 5-10 years.


Author(s):  
Maria Kasatenkova ◽  
Maria Kasatenkova ◽  
Nicolay Kasimov ◽  
Nicolay Kasimov ◽  
Mihail Lychagin ◽  
...  

The last 1978-1995 transgression of the Caspian Sea caused the development of marsh-lagoon system along the Western Caspian seashore. Due to salt marshes are very vulnerable to sea-level fluctuations, complex and dynamic system, they may be considered as a regional model of rapid environmental transformation. Changing conditions of migration in the soils of marsh-lagoon landscapes during the sea-level rise influenced on the migration of elements of variable valency, primarily Fe and Mn, but also Zn, Cu, Pb, Ni, Co, leading to their mobilization in slightly alkaline and neutral reducing conditions and subsequent deposition on the geochemical barriers. That led to the emergence of landscape-geochemical anomalies of Fe and heavy metals in the soils of salt marshes with a characteristic time of formation of any persistent anomalies during 5-10 years.


2015 ◽  
Vol 11 (5) ◽  
pp. 3554-3558 ◽  
Author(s):  
V.M. Abbasov ◽  
M.C. İbragimova ◽  
A.D. Guliyev ◽  
T.A. Ibragimova ◽  
L.M. Efendiyeva ◽  
...  

The article presents the results of studies on the metal-based composites on the basis of copolymers and block copolymers of styrene with butoxymethyl methacrylate (BOMMA) as a catalyst in the oxidation process of naphthene paraffin fraction, which was obtained by extraction method of  dearomatization of diesel fraction. It was shown that at low concentrations of metals of variable valency in the content of the catalyst here is sufficiently high yield of synthetic petroleum acids.


2012 ◽  
Vol 6 (3) ◽  
pp. 339-343 ◽  
Author(s):  
Oleksandr Ivashchuk ◽  
◽  
Viktor Reutskyy ◽  
Sergiy Mudryy ◽  
Oleksandr Zaichenko ◽  
...  

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