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The structure of a disulfide bond can be described by its χ ss dihedral angle between the C β −S γ −S γ −C β atoms, which is usually close to ±90°. The disulfide bond stabilizes the folded form of a protein in several ways: It holds two portions of the protein together, biasing the protein towards the folded topology.
Diphosphenes, with the formula R 2 P 2, formally contain phosphorus-phosphorus double bonds. These phosphorus(I) species are rare but are stable provided that the organic substituents are large enough to prevent catenation. Bulky substituents also stabilize phosphorus radicals. Many mixed-valence compounds are known, e.g. the cage P 7 (CH 3) 3.
White phosphorus, yellow phosphorus or simply tetraphosphorus (P 4) exists as molecules of four phosphorus atoms in a tetrahedral structure, joined by six phosphorus—phosphorus single bonds. [1] The free P 4 molecule in the gas phase has a P-P bond length of r g = 2.1994(3) Å as was determined by gas electron diffraction . [ 2 ]
Although the first phosphorus compounds observed to act as cholinesterase inhibitors were organophosphates, [85] the vast majority of nerve agents are instead phosphonates containing a P-C bond. Only a handful of organophosphate nerve agents were developed between the 1930s and 1960s, including diisopropylfluorophosphate , VG and NPF .
An adult with healthy diet consumes and excretes about 1–3 grams of phosphorus per day, with consumption in the form of inorganic phosphate and phosphorus-containing biomolecules such as nucleic acids and phospholipids; and excretion almost exclusively in the form of phosphate ions such as H 2 PO − 4 and HPO 2− 4. Only about 0.1% of body ...
Since orthophosphoric acid has three −OH groups, it can esterify with one, two, or three alcohol molecules to form a mono-, di-, or triester. See the general structure image of an ortho- (or mono-) phosphate ester below on the left, where any of the R groups can be a hydrogen or an organic radical. Di- and tripoly- (or tri-) phosphate esters ...
General ester of phosphonic acid; in fact, the phosphorus has a formal charge of +1, the oxygen above it has a formal charge of −1, and the bond between them is single. In organic chemistry, phosphonates or phosphonic acids are organophosphorus compounds containing C−PO(OR) 2 groups, where R is an organic group (alkyl, aryl).
The C–P–C bond angles are approximately 98.6°. [3] The C–P–C bond angles are consistent with the notion that phosphorus predominantly uses the 3p orbitals for forming bonds and that there is little sp hybridization of the phosphorus atom. The latter is a common feature of the chemistry of phosphorus.