Phosphorus V

The phosphorus(V) oxide is then reduced by coke, and phosphorus vapour and carbon monoxide are produced ... 

Dinitrogeri pentoxide is the anhydride of nitric acid and is prepared by removing water from pure nitric acid by means of phosphorus (V) oxide. It is a crystalline solid having the ionic structure of (N02) (N03) , nitronium nitrate (the nitronium ion is mentioned later). It decomposes above 273 K, thus ... 

Phosphorus forms a number of oxides, the best established being phosphorus(lll) oxide, P40f, and phosphorus(V) oxide, P40,o-The + 5 oxide is the more stable and the + 3 oxide is easily oxidised. 

The most important property of phosphorus(V) oxide is its great tendency to react with water, either free or combined. It reacts with ordinary water with great vigour, and much heat is evolved trioxo-phosphoric(V) acid is formed, but the local heating may convert some of this to tetraoxophosphoric(V) acid ... 

Phosphorus(V) oxide will remove water from acids to give the acid anhydride. For example, if nitric acid is distilled with it. dinitrogen pentoxide is formed ... 

Phosphorus(V) oxide is an extremely effective desiccating agent, reducing the vapour pressure of water over it to a negligibly small... 

Tetraoxophosphoric acid, H3PO4 — This is prepared in the laboratory either by dissolving phosphorus(V) oxide in water (giving trioxophosphoric acid) and then heating to give the tetraoxo-acid or by heating violet phosphorus with 33% nitric acid, which oxidises it thus ... 

It is also obtained by the dehydration of concentrated sulphuric acid with phosphorus(V) oxide ... 

An important reason for low coordination of iodide ions is that high coordination implies a high oxidation state of the central atom, which often (but not always) means high oxidising power— and this means oxidation of the easily oxidised iodide ligands. Thus the nonexistence of, for example, phosphorus(V) pentaiodide is to be explained by the oxidation of the iodide ligands and reduction of phosphorus to the -(-3 state, giving only PI3, not PI5. 

Dichlorine h ptoxide, CljO, is the most stable of the chlorine oxides. It is a yellow oil at room temperature, b.p. 353 K, which will explode on heating or when subjected to shock. It is the anhydride of chloric(VlI) acid (perchloric acid) from which it is prepared by dehydration using phosphorus(V) oxide, the acid being slowly reformed when water is added. 

Examples P2O5, diphosphorus pentaoxide or phosphorus)V) oxide Hgj, mercury(I) ion or dimercury(2-l-) ion K2[Fe(CN)g], potassium hexacyanoferrate(II) or potassium hexacyanofer-rate(4—) PbJPb 04, dilead(II) lead(IV) oxide or trilead tetraoxide. 

Phosphorus(V) sulfide reacts with olefins, amines, Grignard reagents, and terpenes (6,26) as follows ... 

Table 10. Properties of Allotropic Forms of Phosphorus(V) Oxide...

A reaction of mixed molybdenum polyoxometalates (POMs) with cyanine dye has been used for highly selective and sensitive spectrophotometric determination of phosphorus(V) and arsenic(V). Color of the solution is considerably changed by reaction of Keggin POMs with styrene cyanine dyes. Derivatives of l,3,3-threemethyl-3//-indol - astrazone violet (AV 3R), astrazone rose, astrazone yellow, astrazone red were investigated. 

The reaction of silylated phosphorus(V) itnides with anhydrous hydrogen fluoride gives high yields of alkylenebis(ditluorophosphoranes) [Sf] (equation 19). 

One of the most widely used methods for the formation of phosphate esters involves the conversion of a P-N bond of a phosphorus(III) compound to a P-O bond by ROH, catalyzed by l//-tetrazole, followed by oxidation to the phosphorus(V) derivative ... 

The propensity of phosphorus(III) compounds to oxidize to phosphorus(V) by formation of an additional P=0 bond is well illustrated by the... 

Pentabromphosphor, n. phosphorus penta-bromide, phosphorus(V) bromide, pentacarbocyclisch, a. pentaearbocyelie. Pentathionsaure, /. pentathionie aeid. pentazyklisch, a. pentaeyelie. 

Phosphor-athcr, m. phosphoric ether (ester of phosphoric acid, specif, ethyl phosphate), -basis, phosphorus base, -bestimmung, /. determination of phosphorus, -blei, n. lead phosphide Min.) pyromorphite. -bombe, f. phosphorus bomb. -brandgranate, /. phosphorus incendiary shell, -brei, m. phosphorus paste, -bromid, n. phosphorus bromide, specif, phosphorus pentabromide, phos-phorus(V) bromide, -bromijr, n. phosphorus tribromide, phosphorus(III) bromide, -bronze, /. phosphor bronze, -calcium, n. calcium phosphide, -chlorid, n. phosphorus chloride, specif, phosphorus pcntachloride, phosphorus(V) chloride, -chloriir, n. phosphorous chloride (phosphorus trichloride, phosphorus(III) chloride), -dampf, tn. phosphorus vapor or fume, -eisen, n. ferrophos-phorus iron phosphide, -eisensinter, m. diadochite. 

In all the above methods the element is weighed as the oxide, BeO, which is somewhat hygroscopic [compare aluminium(III) oxide]. The ignited residue, contained in a covered crucible, must be cooled in a desiccator containing concentrated sulphuric acid or phosphorus(V) pentoxide, and weighed immediately it has acquired the laboratory temperature. 

The chromium in the substance is converted into chromate or dichromate by any of the usual methods. A platinum indicator electrode and a saturated calomel electrode are used. Place a known volume of the dichromate solution in the titration beaker, add 10 mL of 10 per cent sulphuric acid or hydrochloric acid per 100 mL of the final volume of the solution and also 2.5 mL of 10 per cent phosphorus) V) acid. Insert the electrodes, stir, and after adding 1 mL of a standard ammonium iron)II) sulphate solution, the e.m.f. is measured. Continue to add the iron solution, reading the e.m.f. after each addition, then plot the titration curve and determine the end point. 

When phosphorus burns in an ample supply of air, it forms phosphorus(V) oxide, P4O]0 (5). This white solid reacts so vigorously with water that it is widely used in the laboratory as a drying agent. Phosphorus(V) oxide is the anhydride of phosphoric acid, H3P04 (6) ... 

---