“…Compounds M X with M"Ca, Sr, Ba and X"Bi, As, Sb were found to be tetragonal (7}9) Compounds M Bi with M"Ca, Sr, Ba have been the most studied: Ba Bi (8, 10) was described as orthorhombic with the -Yb Sb structure-type and Ca Bi hexagonal (11) with the Mn Si structure-type. The isostoichiometric compound Sr Bi displays the two crystallographic hexagonal (8) and orthorhombic (10) structures. The study of compounds M X , M"Ca, Sr, Ba and X"Bi, Sb, and their reactivity toward halogens and sulfur (12) was carried out later.…”