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Phosphorus pentabromide is a reactive, yellow solid of formula P Br 5, which has the structure [PBr 4] + Br − (tetrabromophosphonium bromide) in the solid state but in the vapor phase is completely dissociated to PBr 3 and Br 2.
Hume-Rothery rules, named after William Hume-Rothery, are a set of basic rules that describe the conditions under which an element could dissolve in a metal, forming a solid solution. There are two sets of rules; one refers to substitutional solid solutions, and the other refers to interstitial solid solutions.
Cyanobacteria such as these carry out photosynthesis. Their emergence foreshadowed the evolution of many photosynthetic plants and oxygenated Earth's atmosphere. Biological carbon fixation, or сarbon assimilation, is the process by which living organisms convert inorganic carbon (particularly carbon dioxide, CO 2) to organic compounds.
The propensity for any two substances to form a solid solution is a complicated matter involving the chemical, crystallographic, and quantum properties of the substances in question. Substitutional solid solutions, in accordance with the Hume-Rothery rules, may form if the solute and solvent have: Similar atomic radii (15% or less difference)
The main carboxylating enzyme in C 3 photosynthesis is called RuBisCO, which catalyses two distinct reactions using either CO 2 (carboxylation) or oxygen (oxygenation) as a substrate. RuBisCO oxygenation gives rise to phosphoglycolate , which is toxic and requires the expenditure of energy to recycle through photorespiration .
This is the second core process in photosynthesis. The initial stages occur within picoseconds, with an efficiency of 100%. The seemingly impossible efficiency is due to the precise positioning of molecules within the reaction center. This is a solid-state process, not a typical chemical reaction. It occurs within an essentially crystalline ...
Many of the first metalloproteins consisted of iron-sulphur complexes formed during photosynthesis. [13] Iron is the main redox metal in biological systems. In proteins, it is found in a variety of sites and cofactors, including, for instance, haem groups, Fe–O–Fe sites, and iron–sulfur clusters.
Photosynthesis is the only process that allows the conversion of atmospheric carbon (CO2) to organic (solid) carbon, and this process plays an essential role in climate models. This lead researchers to study the sun-induced chlorophyll fluorescence (i.e., chlorophyll fluorescence that uses the Sun as illumination source; the glow of a plant) as ...