Commercial Red Phosphorus

This is largely amorphous and is made by heating white in closed vessels at about 280-350°C for 48 h. The product of the exothermic reaction is wet milled, boiled with alkali to remove traces of 

Elemental Phosphorus—Density and Bond Length Data 

Brown phosphorus has been obtained by condensing phosphorus vapour containing P molecules on to a surface at liquid nitrogen temperatures. Above 0°C it changes to a mixture of red and white. Fibrous red phosphorus is a red-brown form of phosphorus which contains tubes of pentagonal cross section (similar to those in Hittorf s variety) and all of which lie parallel to the fibre direction [39,48]. 

It seems likely that all forms of red phosphorus (like black (4.26b)) are built from pyramidally linked atoms, the different crystalline varieties representing various kinds of ordered framework, or differing degrees of polymerisation. It is believed by some [49] that nitrogen under very high pressures will form a similar structure to (4.26b). 

It is likely that in many red phosphorus samples polymer growth is terminated by occluded impurity atoms such as halogen, oxygen or hydroxyl. The existence of simple structure (4.26a) has not been substantiated. Amorphous samples may consist of random networks of atoms (4.26c), or randomly arranged P rings linked by short chains of P atoms. 

---

Red phosphorus. Commercial red phosphorus is usually contaminated with small quantities of acidic products. It should be boiled for 15 minutes with distilled water, allowed to settle, decanted through a Buchner funnel, and then washed two or three times with boiling water by decantation. Finally, the phosphorus is completely transferred to the Buchner funnel and washed with hot water untU the washings are neutral. It is dried at 100°, and kept in a desiccator or in a tightly stoppered bottle. 

Preparation and Separation of Phosphorus Tri- and Pentachlorides. Preparation of Phosphorus Trichloride. (Perform the experiment in a fume cupboard ) Wash 15 g of commercial red phosphorus with... 

He found that with ordinary commercial red phosphorus with 98 per cent, phosphorus, there dissolved 0-056 and 0-108 per cent, of phosphorus in respectively 10 and 42 hrs., and with a finely-divided sample 0-092 and 0-116 percent, phosphorus in 10 and 20 hrs. respectively. R. Schenck found that 100 grms. of phosphorus tribromide dissolved 0-2601 grm. of scarlet phosphorus at 172°, and 0-3634 grm. at 184°. E. Baudrimont showed that yellow phosphorus does not attack phosphoryl bromide at the b.p. L. Rosenstein found that soln. of arsenates, and arsenic, antimony, or bismuth salts are not reduced by boiling with red phosphorus but W. Finkelstein found that a nitrobenzene soln. of arsenic trichloride is reduced by yellow phosphorus and arsenic is deposited. 0. Ruff observed that phosphorus reacts with antimony trichloride in the presence of a little aluminium chloride. F. E. Brown and J. E. Snyder observed that vanadium oxytrichloride is without action on red or white phosphorus. 

Although this was a simple, relatively safe mixture, and was a satisfactory primer, it was discontinued after a very short period because of two major disadvantages. It was shown that copper, bismuth, silver, iron, and nickel increased the oxidation rate of red phosphorus to acidic compounds. Primer cups had to be zinc plated to prevent contact with copper. The red phosphorus had to be of high purity, and it was necessary to remove the major impurities (iron and copper) from commercial red phosphorus before use, and to coat the purified material with up to 7.5% aluminum hydroxide which inhibited oxidation. 

Red phosphorus, prepared by digesting 5g of commercial red phosphorus in 50 ml of 5% ammoniacal water on a water bath for 30min. The precipitate is washed with distilled water (Note 2) until the washings are neutral, then with ethanol. Finally, the purified red phosphorus is dried in a forced air oven at 100 °C and stored in a desiccator. 

Commercial red phosphorus has a heat of combustion which exceeds by 568 calories per gramme that of crystallized red phosphorus. 

Lemoine having worked at 440 with commercial red phosphorus prepared between 250 and 300 , the vapor tension should have, as in Troost and Hautefeuille s experiments, increased rapidly up to the tension of saturated vapor from commercial red phosphorus, then decrease to the tension of saturated vapor of red phosphorus prepared at 440 . 

At low dose rate red phosphorus lias the composition (CH3SP2)jj While commercial red phosphorus does not react with Me2S2 with irradiation, red phosphorus, obtained from wliite phosphorus by irradiation in cyclohexane and having the composition (CgHj 1 P4.86)n reacts with Me2S2 when irradiated with °Co y-rays to yield ( 1138)3 and, P(8 H3)2 in the ratio 3.6 1... 

Black phosphorus, which is one of the crystalline modifications of elemental phosphorus, has a crystal structure of three-dimensional network as shown in Figure 2a (45). A plane diagram of its structure is illustrated in Figure 2b-. On the other hand, various structures have been proposed for commercial red phosphorus, which is one of the amorphous modifications of elemental phosphorus. The fact that s... 

P-)6-ring acid, the anions of which have a structure of a six-membered ring, is produced from commercial red phosphorus leads to the idea that commercial red phosphorus has a structure similar to that of black phosphorus, although its structure is not so regular. In order to obtain... 

---