The chemical characteristics of the elements can equally well be studied ... In compounds the polarnumbers are arrived at by assigning to oxygen the value —2 and to hydrogen the value +1.
and the atmosphere, the exterior crust of the earth is composed half of oxygen and one-fourth of silicon, while the other fourth is represented by other elements—aluminum, 7 per cent.; ...
School of Materials Science and Engineering, Key Laboratory of Automobile Materials of MOE, Electron Microscopy Center, Jilin University, Changchun 130012, China ...
Eutrophication and rising water temperatures are taking an increasing toll on the Baltic Sea, leading to dangerous oxygen depletion in deeper water layers and threatening many marine organisms.