Phosphorus oxides molecular structure

The analysis of phosphates and phosphonates is a considerably complex task due to the great variety of possible molecular structures. Phosphorus-containing anionics are nearly always available as mixtures dependent on the kind of synthesis carried out. For analytical separation the total amount of phosphorus in the molecule has to be ascertained. Thus, the organic and inorganic phosphorus is transformed to orthophosphoric acid by oxidation. The fusion of the substance is performed by the addition of 2 ml of concentrated sulfuric acid to — 100 mg of the substance. The black residue is then oxidized by a mixture of nitric acid and perchloric acid. The resulting orthophosphate can be determined at 8000 K by atom emission spectroscopy. The thermally excited phosphorus atoms emit a characteristic line at a wavelength of 178.23 nm. The extensity of the radiation is used for quantitative determination of the phosphorus content. 

Reduction of 1-benzyl-3,4-dibromophospholan oxide (125) with tri-chlorosilane, followed by debromination, gave 1-benzylphosphole. Determination of the molecular structure by X-ray analysis showed slight puckering of the ring with retention of pyramidal configuration at phosphorus. ... 

Trzcinskabancroft, B., Knachel, H., Dudis, D., Delord, T.J. and Marler, D.O. (1985) Experimental And Theoretical-Studies Of Dinudear Gold(I) And Gold(II) Phosphorus Ylide Complexes - Oxidative Addition, Halide Exchange, And Structural-Properties Including The Crystal And Molecular-Structures Of [Au (CH2)2PPh2]2 And [Au(CH2)2PPh2]2(CH3) Bri. Journal of the American Chemical Society, 107(24), 6908-6915. 

Elder, R.C., Florian, L.R., Kennedy, E.R., and Macomber, R.S., Phosphorus containing products from the reaction of propargyl alcohols with phosphorus trihalides. II. The crystal and molecular structure of 2-hydroxy-3,5-di-ferf-butyl-l,2-oxaphosphol-3-ene 2-oxide, /. Org. Chem., 38, 4177, 1973. 

X-Ray.—The crystal and molecular structure of tri-o-tolylphosphine, its oxide, sulphide, and selenide (125) have been compared. The mean P—C bond lengths appear to be determined by the n-electron density along the P—C bond and intramolecular steric interactions, d-Orbital participation was considered to be of little importance.152 X-Ray diffraction established the structure of diphosphinofumarate (126)153 and showed that the phospholanium iodide (127) has an envelope ring with the methyl group at the point of the flap.154 The bicyclic phosphonium bromide (128) has a distorted half-chair phosphorus-containing ring, one of the P—C bonds in the... 

Electron.—The determination of the molecular structure of phosphorus heterocycles by electron diffraction has been reviewed.176 The structures of trimethylphosphine oxide, and the corresponding sulphide in the gaseous phase, have been compared. The rotational freedom of the methyl group appears to be greater for the sulphide, which also has the longer P—C bonds, i.e. 181.8 pm for (144 Ch = S)and 180.9 pm for (144 Ch = O).177 The trifluoromethylphosphoranes (145) and (146) adopt the... 

When cation-radicals from A3-phosphorins such as 188 are formed in the presence of nucleophiles and excess of oxidant, further reaction takes place to give A5-phosphorin derivatives, e.g., 191, generated in the presence of methanol by oxidation of 188 with mercuric acetate.611-614 A crystal and molecular structure determination of a A5-phosphorin shows a planar heterocycle with spd-hybridized phosphorus.615 Anion- and cation-radicals are also obtainable from the A5-phosphorin system.606,611,612... 

RECENT SYNTHETIC, STRUCTURAL, SPECTROSCOPIC, AND THEORETICAL STUDIES ON MOLECULAR PHOSPHORUS OXIDES AND OXIDE SULFIDES... 

Fig. 1. Molecular structure of P408 schematic illustration of the different P—0 linkages. (H) P(III)—Oa ( ) P(III)—Ob (El) P(V)—Ob and ( ) P(V)—Oc. To specify the different atoms forming the phosphorus oxide molecules, the following nomenclature will be used P(III) denotes a formally trivalent phosphorus atom P(V), a formally pentavalent phosphorus atom. Oa denotes a bridging oxygen atom between two P(III) atoms Ob, a bridging atom between a P(III) and a P(V) atom and Oc, a bridging oxygen atom between two P(V) atoms. Od denotes a terminally bonded oxygen atom.

By the end of the nineteenth century, molecular weight determinations carried out by means of vapor density measurements proved that phosphorus(V) and phosphorus(III) oxide in the gaseous state consist of molecules of the compositions P406 (3,86) and P4O10 (87), respectively. However, their molecular structures remained uncertain (see, for example, Ref. 88) until adequate techniques for structure determination such as electron and X-ray diffraction became available (6, 7, 72). 

Determination of the Molecular Structures of Phosphorus Oxides in the Gaseous State... 

Concerning the phosphorus(III/V) oxides, no structural data in the gaseous state are available the only attempt (89) to determine the molecular structure of one of the phosphorus(IIW) oxides, P408, has failed. 

The phosphorus oxide sulfide P403S6 has been described by G. U. Wolf and M. Meisel (178) shows an A3X-type 31P NMR spectrum with signals at +46.0 ppm [P(III)] and + 55.7 ppm [P(V)], the coupling constant being 108 Hz. This corresponds to the molecular structure described in Section III.B. 

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