Prep. From bittern, the liquor left from sea water, after the crystallization of common salt; it is present as bromide of magnesium, and can be obtained by passing a current of chlorine gas through the liquor, which unites with the magnesium, and liberates the bromine; this is often taken up by shaking with ether, which dissolves the bromine, and rises with it to the surface. Subsequent purification is required, usually effected by converting the bromine into bromide of potassium, and again liberating the bromine by means of bin-oxide of manganese and sulphuric acid.
Prop. & Comp. A dark brownish-red liquid by reflected, but hyacinth-red by transmitted light through thin layers; of an intensely disagreeable acrid odour and taste, very volatile, and fumes when exposed to the air; sp. gr. 2.966; soluble in ether, alcohol, and slightly in water; soluble in alkaline solutions, forming salts; precipitates starch of an orange colour.
Therapeutics. Bromine is never administered in its free state, most commonly as bromide of potassium, occasionally as bromide of ammonium and of iron; the effects of these salts are described under the head of their bases.
Adulteration. Bromine sometimes contains iodine. Agitated with a solution of soda, in such proportion that the fluid remains very slightly alkaline, it forms a colourless liquid, which, if coloured by the addition of a small quantity of chlorine, should not become blue on the subsequent addition of starch.