NaClO₃ Crystal Growth and Dissolution by Temperature Cycling in a Sessile Droplet

Sodium chlorate is the most popular compound used to study spontaneous symmetry breaking by means of crystallization. Therefore, it is important to know the behavior of the solid particles. NaClO₃ crystal growth and dissolution are investigated in an aqueous sessile droplet subjected to numerous temperature cycles. On cooling, in addition to the classical formation of repeated elongated fluid inclusions, there is a reproducible appearance of prismatic fluid inclusions (PFIs) at the corners of single crystals. The underlying mechanism involves the complete termination of the (110) face growth and the propagation of the {100} faces, which can close the PFIs. This study reports that on heating, transient donut-like single crystals formed, which could lead to their segmentation, even without stirring the suspension. The systematic addition of other sodium salts with chlorine atoms at different oxidation states did not change these observations.