Selenium boron halides

Zinc—bromine storage batteries (qv) are under development as load-leveling devices in electric utilities (64). Photovoltaic batteries have been made of selenium or boron doped with bromine. Graphite fibers and certain polymers can be made electrically conductive by being doped with bromine. Bromine is used in quartz—halide light bulbs. Bromine is used to etch aluminum, copper, and semi-conductors. Bromine and its salts are known to recover gold and other precious metals from their ores. Bromine can be used to desulfurize fine coal (see Coal conversion processes). Table 5 shows estimates of the primary uses of bromine. 

The other halides of boron and silicon, and also of, phosphorus, sulphur, selenium, tellurium, and iodine, react at once with water, forming hydrogen halide and an acid. The equations are as follows —... 

Alkyl stannyl selenides are also useful nucleophilic selenium reagents. Tri-methylstannyl or tributylstannyl methyl selenides 58 react with halides 59 to produce unsymmetrical selenides 60 in good yields in the presence of a fluoride ion or by treatment with n-butyllithium (Scheme 44) [84]. Tributylstannyl phenyl selenide (61) reacts smoothly with acetals to give monoselenoacetals 62 in the presence of boron trifluoride etherate (Scheme 45 a) [85]. Similar reaction conditions were applied to the regioselective ring opening of epoxides (Scheme 45b) [86]. 

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