Selenium monobromide

Selenium-containing donors, synthesis and manufacture of, 22 212 Selenium dichloride, 22 75t Selenium diethyldithiocarbamate, 22 73t Selenium dioxide, 22 73t, 75t, 88 toxicify of, 22 95 Selenium disulfide, 22 73t Selenium hexafluoride, 22 75t, 87 toxicify of, 22 96 Selenium hypofluorite, 22 75t Selenium iodides, 22 87 Selenium monobromide, 22 75t, 88 Selenium monochloride, 22 75t, 87 in selenium recovery, 22 85 Selenium monoxide, 22 88 Selenium oxidation, selenium recovery via, 22 81-83... 

Combination reactions occur with several nonmetals. With sulfur, it forms sulfur monobromide, S2Br2. With the addition of selenium, products are selenium monobromide, Se2Br2, and selenium tetrabromide, SeBr4. It yields unstable tellurium monobromide, Te2Br2, and a stable tetrabromide, TeBr4,with tellurium. 

The ease with which selenium combines with many other elements to form binary compounds has already been mentioned (p. 299). Only one compound with hydrogen is known, but a series of polyselenides of the alkali metals corresponding to the polysulphides has been obtained. Selenium forms a hexafluoride, SeFG, but no other hexalialide has been isolated. The tetrahalides arc the most stable, and mixed chloro-bromides of quadrivalent selenium, SeCl Br, are known. Selenium monochloride, SeaCla, and selenium monobromide, Se2Br2, also exist as comparatively stable liquids at ordinary temperatures. No compound of selenium and iodine is known. Selenium oxychloride, SeOCl2, and the oxybromide, SeOBr2, are extremely reactive and useful compounds. 

Selenium Monobromide, Se2Br2.—This is produced together with the tetrabromide by the action of boiling bromine on selenium.9 The reaction, which is accompanied by considerable heat evolution, may be moderated by dissolving the bromine in carbon disulphide.10 The substance can also be produced by treating the tetrabromide with selenium at the ordinary temperature.11... 

The action of water on selenium monobromide is analogous to the action on the corresponding chlorine compound, selenium and selenium dioxide being formed. 

Selenium monobromide reacts with gaseous ammonia in a similar way to the corresponding chloride. With liquid ammonia in the presence of ether, it gives the compound Se2N2Br.x... 

From the fact that on reacting with orga no-magnesium compounds selenium monobromide gives rise to organic substances containing a chain linking, —Se—Se—, it is probable that the constitution is to be represented by Br—Se—Se-—Br.2... 

Selenium Tetrabromide, SeBr4, is formed by the action of excess of bromine on selenium or on selenium monobromide, the latter preferably being in solution in carbon disulphide, in order to moderate the vigour of the process.3... 

Selenium Trichlorobromide, SeCl3Br, Selenium Dichlorodi-bromide, SeCl2Br2, and Selenium Chlorotribromide, SeClBr3, have been described as yellow crystalline compounds, the first being obtained by the action of chlorine on selenium monobromide and the last by the action of bromine on selenium monochloride, while the intermediate body has been obtained by the action of chlorine on a mixture of selenium tetrabromide and monobromide.3... 

The majority of the metals react with selenium oxybromide with the production of the corresponding metal bromides, selenium dioxide and selenium monobromide. Zinc, cadmium, chromium, nickel, cobalt, tungsten and tantalum, however, are not attacked even after prolonged heating at 100° C. 

Older names are selenium monobromide and selenous bromide. 

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