Normal values of K were given by nitrogen peroxide, N204, sulphur chloride, S 2 C1 21 silicon tetrachloride, SiC1 4, phosphorus chloride, PC1 3, phosphoryl chloride, POC1 31 nickel carbonyl, Ni(CO) 4, carbon disulphide, benzene, pyridine, ether, methyl propyl ketone; association characterized many hydroxylic compounds: for ethyl alcohol the factor of association was 2.74-2.43, for n-propyl alcohol 2.86-2.72, acetic acid 3.62 -2.77, acetone 1 .
Sulphur trioxide and sulphuric acid oxidize phosphorus oxide, giving the pentoxide and sulphur dioxide, whilst sulphur chloride, S 2 C1 2, gives phosphoryl and thiophosphoryl chlorides, free sulphur and sulphur dioxide.
Phosphoryl trifluoride, POF3, may be obtained by exploding 2 volumes of phosphorus trifluoride with 1 volume of oxygen (Moissan, 1886); by heating 2 parts of finely-divided cryolite and 3 parts of phosphorus pentoxide (Thorpe and Hambly, Jour.
Soc., 188 9, p. 759); or from phosphoryl chloride and zinc fluoride at 40° to 50°.
With chlorine it gives the pentachloride, PC1 5, and with oxygen when heated phosphoryl chloride, POC1 3.
It fumes strongly in moist air, giving hydrochloric acid and phosphoryl chloride, POC13; with water it gives phosphoric and hydrochloric acids.
Phosphoryl trichloride or phosphorus oxychloride, POC1 3, corresponding to phosphoric acid, (HO) 3 P0, discovered in 1847 by Wurtz, may be produced by the action of many substances containing hydroxy groups on the pentachloride; from the trichloride and potassium chlorate; by leaving phosphorus pentoxide in contact with hydrochloric acid: 2P 2 0 5 +3HC1= POC13+3HP03; or by heating the pentachloride and pentoxide under pressure: 3PC15+ P205= 5POC1 3.
Phosphoryl tribromide, POBr 3, is a solid, melting at 45° and boiling„at 195°.