Morphology and crystal growth of structurally related A2BX4- and A2BX3-compounds*

Abstract
The morphological relationship of compounds of glaserite-, Na 2 SO 3 -, low1-K 2 SO 4 - and olivine types is examined. The crystal structures can be retraced to a common basic structure. The morphological lattice is determined by a sign determination with the help of the Goldschmidt complication rule and with Fourier methods. The crystal growth of olivine, having a morphology similar to that of barite, deviates from the other compounds. The differences are indicated with the help of partitions of the three-dimensional space into Dirichlet domains of morphological points. The packings of space-filling polyhedra allow conclusions on growth mechanisms.