The phase rule and its applications . white phosphorus is heated to 44° it Atthis point, therefore, we shall have another triple point, whitephosphorus—liquid—vapour • the pressure at this point has, been calculated to be 3 ThisA point is the intersec-tion of three curves,viz. sublimationcurve, vaporizationcurve, and thefusion curve ofwhite fusion curve,02E, has beendetermined byTammann3 and byFig. 11. G. A. Hulett,4 and it was found that increase of pressure by 1 atm. raises themelting point by 0*029°. The sublimation curve of whitephosphorus has not yet been deter
The phase rule and its applications . white phosphorus is heated to 44° it Atthis point, therefore, we shall have another triple point, whitephosphorus—liquid—vapour • the pressure at this point has, been calculated to be 3 ThisA point is the intersec-tion of three curves,viz. sublimationcurve, vaporizationcurve, and thefusion curve ofwhite fusion curve,02E, has beendetermined byTammann3 and byFig. 11. G. A. Hulett,4 and it was found that increase of pressure by 1 atm. raises themelting point by 0*029°. The sublimation curve of whitephosphorus has not yet been determined. As can be seen from the table of vapour pressures (p. 46),the vapour pressure of white phosphorus has been determinedup to 5000; at temperatures above this, however, the velocitywith which transformation into red phosphorus takes place isso great as to render the determination of the vapour pressureat higher temperatures impossible. Since, however, the differ-ence between white phosphorus and red phosphorus disappears. 1 Boeseken has found the melting point under a pressure of 8 mm. to be4477° {Rec- trav- chiiti., 1907, 26. 289). - Riecke, Zeitschr. physikal. Chem., 1890, 6. 411. 3 Annalen do- Physik., 1898 [3], 66. 492. 4 Zeitschr. physikal. Chem., 1899,28. 666. TYPICAL SYSTEMS OF OXE COMPONENT 49 in the liquid state, the vapour pressure curve of white phosphorusmust pass through the point 01} the melting point of red phos-phorus, and must be continuous with the curve Ovk, the vapourpressure curve of liquid phosphorus (vide infra). Since, asFig. 10 shows, the vapour pressure curve of white phosphorusascends very rapidly at higher temperatures, the breakbetween BOj and dA must be very slight. As compared with monotropic substances like benzophenone,phosphorus exhibits the peculiarity that transformation of themetastable into the stable modification takes place with greatslowness; and further, the time required for the production ofequilibrium between red phospho
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