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Phosphine (IUPAC name: phosphane) is a colorless, flammable, highly toxic compound with the chemical formula P H 3, classed as a pnictogen hydride.Pure phosphine is odorless, but technical grade samples have a highly unpleasant odor like rotting fish, due to the presence of substituted phosphine and diphosphane (P 2 H 4).
Triphenylphosphine (IUPAC name: triphenylphosphane) is a common organophosphorus compound with the formula P(C 6 H 5) 3 and often abbreviated to P Ph 3 or Ph 3 P. It is versatile compound that is widely used as a reagent in organic synthesis and as a ligand for transition metal complexes, including ones that serve as catalysts in organometallic chemistry.
Ph 3 PO is structurally related to POCl 3. [2] As established by X-ray crystallography, the geometry around P is tetrahedral, and the P-O distance is 1.48 Å. [3] Other modifications of Ph 3 PO have been found: For example, a monoclinic form crystalizes in the space group P2 1 /c with Z = 4 and a = 15.066(1) Å, b = 9.037(2) Å, c = 11.296(3) Å, and β = 98.47(1)°.The orthorhombic ...
The molecule is tetrahedral, with point group symmetry of T d, as expected for a four-coordinate metal complex of a metal with the d 10 configuration. [4] Even though this complex follows the 18 electron rule, it dissociates triphenylphosphine in solution to give the 16e − derivative containing only three PPh 3 ligands:
This would result in the geometry of a regular tetrahedron with each bond angle equal to arccos(− 1 / 3 ) ≈ 109.5°. However, the three hydrogen atoms are repelled by the electron lone pair in a way that the geometry is distorted to a trigonal pyramid (regular 3-sided pyramid) with bond angles of 107°.
Crystallographic characterization of the colourless ylide reveals that the phosphorus atom is approximately tetrahedral. The PCH 2 centre is planar and the P=CH 2 distance is 1.661 Å, which is much shorter than the P-Ph distances (1.823 Å). [5]
According to single crystal X-ray diffraction the compound adopts a slightly distorted square planar structure. [7] In analyzing the bonding, it is a complex of Rh(I), a d 8 transition metal ion. From the perspective of the 18-electron rule, the four ligands each provides two electrons, for a total of 16-electrons.
Molecular geometry is the three-dimensional arrangement of the atoms that constitute a molecule. It includes the general shape of the molecule as well as bond lengths , bond angles , torsional angles and any other geometrical parameters that determine the position of each atom.