Prepd from the elements, excess Br is removed by heating to 50° in a current of CO2: Bornemann, Ann. 189, 202 (1877); Terwogt, Z. Anorg. Allg. Chem. 47, 203 (1905); Gmelins, Iodine (8th ed.) 8, p 631 (1933); Schmeisser in Handbook of Preparative Inorganic Chemistry vol. 1, G. Brauer, Ed. (Academic Press, New York, 2nd ed., 1963) p 291-292. Crystal structure: Swink, Carpenter, Acta Crystallogr. 24B, 429 (1968).