Oxide phosphorus

Known Phosphorus Oxides and Oxide Sulfides. Generalized Formula P40 Sm 

At that time, they used a reaction temperature of 550-600°C, used a pressure of 70 Torr, and purified N20 as the oxidizing agent. The yield of P406 with respect to P4 was up to 70-80%. Further improvements of the production of P406 are listed in Table II (see also Ref. 42, especially for thermodynamical and equilibrium considerations). 

Other trials reported for the preparation of P406 from PC13 are 

1 Under somewhat similar conditions, E. J. Russell (66) was able to recover the same substance. 

2 Pure P4O7 is also formed in the reaction of P406 with alkali metal oxides, e.g., K20 or Cs20 (78). 

Although crystals of the /3-phase of phosphorus(IIW) oxides with a high content of P4O8 can be obtained (7, 71, 72, 73), nobody has yet been able to isolate the pure oxide. D. Heinz et al. assumed that phospho-rus(IIW) oxide mixtures that contain 95% of P4O8 form only amorphous solids. This may be due to the fact that P4O8 has the lowest molecular symmetry of all phosphorus oxides considered here. Further investigation of this subject is still in progress. 

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 P4O6 (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). 

Phosphorus forms five oxides of composition P4OB, n = 6, 7, 8, 9 or 10. The molecular structures of the first and the last member of the series have been determined in the gas phase. See Fig. 20.10. The four phosphorus atoms in tetraphosphorus hexoxide, P4O6, are 

The 1998 edition of the standard English language compilation of thermodynamic data, the NIST-JANAF Thermochemical Tables, gives the standard enthalpy of formation of gaseous P4O6 at 298 K as -2214 34 kJ mol [19]. This value is based on an experimental determination of the enthalpy of formation for the crystalline compound published in 1952. This determination was 11 years later shown to be in error by about 600 kJ moP [20] (The reader has now been warned Even the most authoritative compilation of experimental data may contain entries that are in serious error ) The new value for the enthalpy of formation of the solid leads to a gas phase enthalpy of formation of Af//° = -1606 40 kJ moP [21]. Calculation of the energy of atomization and division by 12, yields a P-O mean bond energy of MBE(P-O) = 362 kJ mol .  

The solid face structures of the intermediate members of the series P4OB show that they differ only in the number of terminal, doubly bonded O atoms. 

In Eig. 20.11 we compare the structures of PF3 and PCI3 with the sfructures of the corresponding phosphoryl trihalides, OPX3. Both the PO bond distances and the thermochemical bond energies calculated by transfer of the P-X bond energies from the trihalides, indicate that the PO bonds are best described as double. 

We end our discussion of oxides, oxohalides, and oxoacids of C, N, P, S, and Cl by noting that in all the compounds that we have considered, two-coordinate oxygen atoms are best described as forming two single bonds, while (with the possible exception of the O atoms in CIO2) all mono-coordinate oxygen atoms are best described as doubly bonded. 

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White Phosphorus Oxidation. Emission of green light from the oxidation of elemental white phosphoms in moist air is one of the oldest recorded examples of chemiluminescence. Although the chemiluminescence is normally observed from sotid phosphoms, the reaction actually occurs primarily just above the surface with gas-phase phosphoms vapor. The reaction mechanism is not known, but careful spectral analyses of the reaction with water and deuterium oxide vapors indicate that the primary emitting species in the visible spectmm are excited states of (PO)2 and HPO or DPO. Ultraviolet emission from excited PO is also detected (196). 

About 80-90% of the elemental P produced is reoxidized to (pure) phosphoric acid (p. 521). The rest is used to make phosphorus oxides (p. 503). sulfides (p. 506), phosphorus chlorides and oxochloride (p. 4%). and organic P compounds. A small amount is convened to red phos rftorus (see below) for use in the striking surface of matches for pyrotechnics and as a flame retarding agent (in polyamides). Bulk price for P4 is S2.00/kg. 

Phosphorus oxides, sulfides, selenides and related compounds... 

H.21 Phosphorus and oxygen react to form two different phosphorus oxides. The mass percentage of phosphorus in one of these oxides is 43.64% in the other, it is 56.34%. 

This reaction is an example of a hydrolysis reaction, a reaction with water in which new element-oxygen bonds are formed. Another example is the reaction ot PC15 (phosphorus oxidation state +5) with water to produce phosphoric acid, H3P04 (also phosphorus oxidation state - -5) ... 

The structures of the phosphorus oxides are based on the tetrahedral P04 unit, which is similar to the structural unit in the oxides of its neighbor silicon (see Section 14.19). White phosphorus burns in a limited supply of air to form phos-phorus(III) oxide, P406 (2) ... 

Spectroscopic, and Theoretical Studies on MoleculEu- Phosphorus Oxides and Oxide Sulfides J. Clade, F. Frick, and M. Jansen... 

If heated with sodium oxide or at ambient temperature when water traces are present, phosphorus oxide reacts very violently. 

Considering the phosphorus oxidation reaction given earlier, and applying the Van t Hoff isotherm for nonequilibrium conditions,... 

Long SR, Christesen SD. 1989. Laser ionization studies of organophosphonates and phosphorus oxide radicals. Journal of Physical Chemistry 93(18) 6625-6628. 

The affinity of [Au(CN)2] for primary, secondary, and tertiary amines is very low at pH values typical for cyanide feed solutions, but in 1983 Mooiman et al. showed that the addition of solvating phosphorus(V) oxides enhanced extraction at higher pH.335,336 During the course of this work it was discovered that TBP and DBBP (see Table 6) could themselves extract gold.337 This led to subsequent investigations on phosphates and phosphorus oxides.333... 

Ethyl acetate (500 mL) is purified by washing with 100 mL of 5% sodium carbonate solution, followed by 100 mL of saturated sodium chloride solution, drying over potassium carbonate and filtering. It is then heated at reflux over phosphorus oxide P2O5) for 3-12 hr and distilled from P2O5.3... 

Chloroform was purchased from Fisher Scientific Company and distilled from phosphorus oxide (P2O5) immediately before use and added to the reaction mixture via syringe. 

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