Solution-growth, crystal system and transformation of crystals of phase II RbNO₃

Abstract

It has proved possible to grow small single crystals of phase 11 of rubidium nitrate above 220°C.  These are used to examine the crystal system and polymorphic transformation of this phase. Rhombohedralsymmetry has been deduced from polarized light microscopy. The crystals undergo a regular shape change in the transformations 11 → I → 11. This implies a coordinated structural rearrangement which can be related to a lattice deformation.