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Phosphorus pentasulfide is obtained by the reaction of liquid white phosphorus (P 4) with sulfur above 300 °C. The first synthesis of P 4 S 10 by Berzelius in 1843 [ 5 ] was by this method. Alternatively, P 4 S 10 can be formed by reacting elemental sulfur or pyrite , FeS 2 , with ferrophosphorus , a crude form of Fe 2 P (a byproduct of white ...
Photosynthetic water splitting (or oxygen evolution) is one of the most important reactions on the planet, since it is the source of nearly all the atmosphere's oxygen. Moreover, artificial photosynthetic water-splitting may contribute to the effective use of sunlight as an alternative energy-source.
The word oxygen in the literature typically refers to molecular oxygen (O 2) since it is the common product or reactant of many biogeochemical redox reactions within the cycle. [37] Processes within the oxygen cycle are considered to be biological or geological and are evaluated as either a source (O 2 production) or sink (O 2 consumption). [36 ...
The high-energy oxidized tyrosine gives off its energy and returns to the ground state by taking up a proton and removing an electron from the oxygen-evolving complex and ultimately from water. [4] Kok's S-state diagram shows the reactions of water splitting in the oxygen-evolving complex.
The underlying force driving these reactions is the Gibbs free energy of the reactants relative to the products. If donor and acceptor (the reactants) are of higher free energy than the reaction products, the electron transfer may occur spontaneously. The Gibbs free energy is the energy available ("free") to do work.
The oxygen-evolving complex (OEC), also known as the water-splitting complex, is a water-oxidizing enzyme involved in the photo-oxidation of water during the light reactions of photosynthesis. [3] OEC is surrounded by 4 core proteins of photosystem II at the membrane-lumen interface.
In these light-dependent reactions, some energy is used to strip electrons from suitable substances, such as water, producing oxygen gas. The hydrogen freed by the splitting of water is used in the creation of two important molecules that participate in energetic processes: reduced nicotinamide adenine dinucleotide phosphate (NADPH) and ATP.
Water cycle – moves water continuously on, above and below the surface shifting between states of liquid, solution, ice and vapour; Methane cycle – moves methane between geological and biogeochemical sources and reactions in the atmosphere; Hydrogen cycle – a biogeochemical cycle brought about by a combination of biological and ...