March io, 1892] 



NATURE 



449 



which is deposited in a most beautiful manner in regular annuli 

 all up the tube to the very top. When the oxide is placed in 

 contact with oxygen in an apparatus in which the pressure can 

 be rapidly diminished, the oxidation is seen to be accompanied 

 by a phosphorescent glow, flickering up and down throughout 

 the whole inclosed space, similar to that which occurs under the 

 same circumstances with phosphorus itself. Moreover, this 

 phenomenon is observed with the purest specimens distilled in 

 vacuo. If the temperature is increased, the phosphorescence 

 is brought about at pressures near the atmospheric, and if it is 

 raised to 70° C, phosphorescence gives place to actual com- 

 bustion, which, however, may be at once reduced to mere 

 phosphorescence by diminishing the pressure. If the oxide is 

 thrown into oxygen warmed to about 50°, it immediately burns 

 to the pentoxide with a most brilliant flash of flame. 



Action of Halogens. 



When phosphorous oxide is thrown into a vessel containing 

 chlorine gas, it instantly takes fire and burns with a pale green 

 flame. If chlorine is led over the oxide at the ordmary tem- 

 perature, violent combustion also occurs ; but if the vessel con- 

 taining the oxide is cooled by ice, the reaction occurs in a more 

 moderate manner. The product is a clear liquid which is found 

 to be a mixture of phosphorus oxychloride, POCI3, which may 

 be distilled off", and metaphosphoryl chloride, POgCl, which 

 remains as a viscous residue after the distillation of the phos- 

 phorus oxychloride. The reaction occurs in complete accordance 

 with the equation 



P4O6 + 4CI2 = 2POCI3 + 2PO2CI. 



Bromine also acts with considerable violence upon the oxide, 

 generally with incandescence. Analogous products are eventually 

 obtained as in the case of chlorine ; but if the experiment is so 

 arranged that the vapours of the two substances only are allowed 

 to react at the ordinary temperature, an intermediate reaction 

 occurs with deposition of annuli of large and very perfect 

 crystals of phosphorus pentabromide, PBrg, phosphorus pent- 

 oxide being also formed at the surface of the phosphorous oxide. 



Iodine only slowly reacts with the oxide, and best when the 

 two substances are dissolved in carbon bisulphide and the solu- 

 tion heated in a sealed tube. On cooling, orange-red crystals 

 of P2I4 separate out. 



Action of Sulphur— Formation of a Sulphoxide of Phosphorus. 



Sulphur reacts with the oxide in a most interesting manner, 

 producing a beautifully crystalline addition compound of the 

 empirical formula P.^OjSa. The reaction is best carried out in a 

 sealed tube, about five grams of the oxide and the corresponding 

 quantity of sulphur being placed together in the tube, which has 

 previously been filled with carbon dioxide or nitrogen. The 

 tube is fixed upright, and its lower portion, containing the 

 mixture, is heated in a glycerine bath. No reaction occurs, the 

 two liquids remaining in separate layers, until a temperature 

 in the neighbourhood of 160° is attained, when sudden and very 

 violent combination takes place, the tube being usually shattered 

 into fragments if more than 5 grams of the oxide are employed. 

 The sulphoxide produced is a pale yellow solid substance which 

 melts at about 102°, and boils without decomposition at 295°. 

 When heated in vcuuo it sublimes largely in the form of tetra- 

 gonal prisms of considerable size, quite colourless and trans- 

 parent ; a certain amount frequently condenses in a vitreous 

 form, which eventually devitrifies into feathery aggregates of 

 the tetragonal prisms. Occasionally long needles, elongated 

 tetragonal prisms, are formed. A very slight residue usually 

 remains of sulphur, to which the yellowish colour of the crude 

 product is probably due. The sulphoxide is soluble in carbon 

 bisulphide, and the solution deposits it again in tetragonal 

 prisms on evaporation. 



As phosphorus sulphoxide is undecomposed even at 400° C, 

 it has been found possible to determine its vapour density by 

 Victor Meyer's method in an atmosphere of nitrogen. The 

 numbers obtained agree with the double formula P4O6S4. 

 Hence phosphorus sulphoxide is a direct sulphur addition 

 product of phosphorous oxide. 



It is deliquescent, and is decomposed by water with liberation 

 of sulphuretted hydrogen and formation of phosphoric acid. 



Other Reactions of Phosphorous Oxide. 



Ammonia gas, when led over melted phosphorous oxide, 



causes immediate ignition of the mass. When the oxide is 



NO. I 167, VOL, 45] 



dissolved in ether, however, the action is more manageable, 

 and a new white solid compound is formed. This compound is 



/NHo 

 the diamide of phosphorous acid, P;^ NHI. It is an amorphous 



\0H 

 powder which dissolves instantly in water with production of 

 flame. Dilute hydrochloric acid liberates pure non-spon- 

 taneously inflammable phosphoretted hydrogen from it, owing 

 to the decomposition, at the high temperature brought about by 

 the reaction, of the phosphorous acid first produced. 



Hydrochloric Acid gas converts the oxide into phosphorus 

 trichloride and phosphorous acid, the former being readily 

 decanted from the latter at the close of the experiment. 

 P4O6 + 6HC1 - 2PCI3 + 2H3PO3. 



Concentrated sulphuric acid deflagrates violently with phos 

 phorous oxide with production of flame, formation of phosphori 

 acid, and liberation of sulphur dioxide. 



Caustic alkalies, when tolerably concentrated, at once decom- 

 pose the oxide with production of a flame of burning phos- 

 phoretted hydrogen, red phosphorus being deposited, and a 

 phosphate formed. 



Sulphur chloride and phosphorus pentachloride respectively 

 react with great energy with the oxide, the resulting liquid pro- 

 ducts being immediately raised to the boiling-point. When the 

 reactions are performed in vessels cooled by ice, the products 

 may be collected and examined. Sulphur chloride yields a 

 mixture of oxychloride and sulphochloride of phosphorus, 



P4O6 -f 6S2CI2 = 2POCI3 -f 2PSCI3 -f 2SO2 -f 8S. 

 Phosphorus pentachloride produces a mixture of oxychloride and 

 trichloride of phosphorus, 



P4O6 -f 6PCI5 = 6POCI3 -{- 4PCI3. 



Ethyl alcohol instantly sets fire to phosphorous oxide. The 

 reaction may readily be moderated, however, by cooling the 

 vessel by ice, and under these circumstances a new liquid, diethyl 



/OC2H3 

 phosphorous acid P0-OC2H3, is produced. This liquid possesses 



\0H 

 a strong garlic-like odour, boils at 184°-! 85^, and has a specific 

 gravity of I '0749 at I5°'5. 



An account of the properties of phosphorous oxide would not 

 be complete without a reference to its physiological action. Most 

 people are aware that persons engaged in lucifer-match making 

 occasionally suffer terribly from disease of the lower jaw, and it 

 is found that this is due to the direct action of the fumes upon 

 the bone. It would appear that this deplorable action is directly 

 traceable to the vapour of the volatile phosphorous oxide now 

 described, for this oxide is found to be largely formed when 

 phosphorus oxidizes without igniting ; and if any benefit in the 

 way of increased precautions against such action should follow 

 from th2 further knowledge now gained concerning this sub- 

 stance, none will rejoice more heartily than those who have 

 attempted to place its chemical history upon a surer foundation. 



A. E. TUTTON. 



UNIVERSITY AND EDUCATIONAL 

 INTELLIGENCE. 



Oxford.— Mr. George B. Grundy, B.A., Brasenose College, 

 has been elected to a Geographical Studentship (see Novem- 

 ber 19, 1891, p. 70). This student, after preliminary study at 

 Oxford, or at some other place appointed by the electors, will 

 be expected to reside at least three months in the region he is 

 investigating, and to forward the results of his work to the Koyal 

 Geographical Society. 



A meeting of the Ashmolean Society was held in the Museum 

 on Monday, March 7, Mr. E. B. Poulton, F.R.S ,in the chair. 

 The Rev. F. J. Smith, Trinity College, Mellard Lecturer, was 

 prevented by illness from giving his paper on some of the uses of 

 photography in scientific research. Mr, Veley, University 

 College, read a paper on some chemical transformations of nitric 

 and nitrous acids. 



Mr. F. E. Weiss, Assistant Professor of Botany at University- 

 College, London, has been appointed Professor of Botany at 

 Owens College, Manchester. 



Mr. Wyndham R. Dunstan, the Director of the Research 

 Laboratory connected with the Pharmaceutical Society, has been 

 elected Lecturer on Chemistry at St. Thomas's Hospital Medical 

 School, in succession to the late Dr. Bernays. 



