Phosphorus vapour

At temperatures above 800°C dissociation of the tetra atomic vapour takes place. This is appreciable at 900°C, and at 1700°C roughly equal numbers of P4 and P2 molecules are in equilibrium (4.27). Emission spectra indicate that the P2 molecule contains a triple bond with P=P=1.875A. The equilibrium lies to the left-hand side except for high temperatures or low pressures. 

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

Arsenic and antimony resemble phosphorus in having several allotropic modifications. Both have an unstable yellow allotrope. These allotropes can be obtained by rapid condensation of the vapours which presumably, like phosphorus vapour, contain AS4 and Sb4 molecules respectively. No such yellow allotrope is known for bismuth. The ordinary form of arsenic, stable at room temperature, is a grey metallic-looking brittle solid which has some power to conduct. Under ordinary conditions antimony and bismuth are silvery white and reddish white metallic elements respectively. 

The trichloride is obtained as a liquid, boiling point 349 K, when a jet of chlorine burns in phosphorus vapour. Care must be taken to exclude both air and moisture from the apparatus since phosphorus trichloride reacts with oxygen and is vigorously hydrolysed by water, fuming strongly in moist air. The hydrolysis reaction is ... 

Monorubium acetylide and monocaesium acetylide incandesce with warm phosphorus. Lithium acetylide and sodium acetylide bum vigorously in phosphorus vapour, and the potassium, rubidium and caesium analogues should react with increasing violence. 

Iseler, G. W. et al., Int. Conf. Indium Phosphide Relat. Mater., 1992, 266 Reaction of beryllium, copper, manganese, thorium or zirconium is incandescent when heated with phosphorus [1] and that of cerium, lanthanum, neodymium and praseodymium is violent above 400°C [2], Osmium incandesces in phosphorus vapour, and platinum bums vividly below red-heat [3], Red phosphorus shows very variable vapour pressure between batches (not surprising, it is an indeterminate material). This leads to explosions when preparing indium phosphide by reactions involving fusion with phosphorus in a sealed tube [4],... 

I. Remsen and E. H. Keiser considered that they had obtained a special allotropic form of phosphorus by suddenly cooling the vapour of phosphorus by iced-water. The product is here red phosphorus, for, as shown by A. Stock and co-workers, red phosphorus can be produced by suddenly quenching phosphorus vapour at 900 -1175. H. M. Vernon reported that rhombic phosphorus, i.e. rhombic crystals of phosphorus, can be obtained by slowly cooling liquid phosphorus. This observation, however, remains unverified ... 

Fig. 6.—Dissociation Pressures of Phosphorus Vapour at Different Temperatures.

It is assumed that violet phosphorus is the stable form but the metastable state of the element should have a higher vap. press, than the stable state, hence, it is further assumed that the mols. of the black and violet forms of phosphorus are not built up of the same kind of molecules. M. Centnerszwer found the partial press, of phosphorus vapour at 20° in an atm. of hydrogen is 0-0253 mm. oxygen, 0-0251 mm. carbon dioxide, 0-0312 mm. coal-gas, 0-0242 mm. air and iodobenzene, 0-0253 mm. W. Herz found that the constant c in the equation Bxj82 —TilT2-j-c(T2—Ti) varies from 0-001374 to 0-001990. Bx and 82 denote the b.p. of two liquids at any press., and Tx and Tz, the b.p. of the same liquids at another press. 

D. Reichenstein measured the electrode potential of phosphorus in soln. of potassium hydroxide, and sulphuric acid. R. Schenck found the potential difference of the hydrogen-phosphorus couple to be 0-168 volt at 13-6°, so that the phosphorus electrode is negative to that of hydrogen. W. Beetz studied the gas-cell with phosphorus vapour, and platinum with occluded hydrogen O. S. Duffendack and H. Huthsteiner, the low- voltage arc in phosphorus vapour. W. Busse measured the distribution of the sizes of the ions in phosphorus vapour and found that there is a continuous gradation from the largest to the smallest. 

Yellow phosphorus is commonly sold in the form of waxy, transparent sticks which are usually preserved under water, because the element is so readily oxidized and inflamed when exposed to air. Yellow phosphorus fumes in air, and it then appears to have a peculiar odour recalling that of garlic. As remarked by C. P. Schonbein,1 phosphorus vapour has probably no smell what is actually... 

C. A. Edwards and A. J. Murphy measured the rate at which copper reacts with phosphorus vapour between 600° and 700°, and referred the results to the expression dw/dt—kA/D, where k is a constant w denotes the number of grams converted into phosphide in the time t min. A, the area of the exposed copper in sq. cm. and D, the depth in cm. 

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