Orientation of Calcium Molybdate (CaMoO₄) and Other Single Crystals Having the Scheelite Structure

Values of interplanar angles useful in distinguishing the [100] from the [110] direction in CaMoO₄ are given to facilitate orientation by analysis of back-reflection Laue patterns. The distinction between the [001] and $$ directions in the scheelite structure is discussed and examples of physical properties dependent upon this distinction are given. The [001] direction is denned in terms of the crystal structure and a procedure for identifying [001] using Laue patterns is described. The same distinction applies to certain nonpolar directions of all crystals belonging to the following nonenantio morphous point groups: $$ , m, 2/m, mmm, $$ , 3m, $$ m, $$ , 4/m, 4/mmm, $$ , 6/m, 6/mmm, m3 and m3m.