Can optically uniaxial Ni-I-boracite be structurally cubic?

Abstract
Crystals of cubic Ni3B7O13I grown by vapour transport with growth direction ⟨110⟩ are optically uniaxial. Some experiments are described which test possible explanations of this anisotropy: but the structure is found to be truly cubic and the anisotropy remains unexplained.

This publication has 5 references indexed in Scilit: