Triphenylphosphine oxide

is structurally related to . As established by X-ray crystallography, the geometry around P is tetrahedral, and the P-O distance is 1.48 Å. Other modifications of have been found: For example, a monoclinic form crystallizes in the space group P21/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 modification crystallizes in the space group Pbca with Z = 4 and 29.089(3) Å, b = 9.1347(9), c = 11.261(1) Å. The oxygen center is relatively basic. The rigidity of the backbone and the basicity of the oxygen center make this species a popular agent to crystallize otherwise difficult to crystallize molecules. This trick is applicable to molecules that have acidic hydrogen atoms, e.g. phenols. ==As a byproduct of organic synthesis==

is a byproduct of many useful reactions in organic synthesis including the Wittig, Staudinger, and Mitsunobu reactions. It is also formed when is employed to convert alcohols into alkyl chlorides: : Triphenylphosphine can be regenerated from its oxide by treatment with a variety of deoxygenation agents, such as phosgene or trichlorosilane/triethylamine: :{{chem2|Ph3PO + SiHCl3 → PPh3 + 1/n (OSiCl2)_{n} + HCl}} Triphenylphosphine oxide can be difficult to remove from reaction mixtures by means of chromatography. It is poorly soluble in hexane and cold diethyl ether. Trituration or chromatography of crude products with these solvents often leads to a good separation of triphenylphosphine oxide. Its removal is facilitated by conversion to its Mg(II) complex, which is poorly soluble in toluene or dichloromethane and can be filtered off. An alternative filtration method where is formed upon addition of may be used with more polar solvents such as ethanol, ethyl acetate and tetrahydrofuran. ==Coordination chemistry==

forms a variety of complexes. A representative complex is the tetrahedral species . is a common impurity in Triphenylphosphine|. The oxidation of by oxygen, including air, is catalysed by many metal ions: : ==References==