Surface structure and degree of coarsening of {111}NaCl surfaces near the thermodynamic equilibrium between crystal and vapour

Thermodynamic study of reconstructed crystal surfaces.

“…For the latter the configurational entropy is negligible due to the high energy cost to form a surface vacancy (Shi and Wortis [25], Kern [26]). So, in agreement with observations at high temperature, we expect that the face (111) eventually formed during vapor growth, breaks into a hill and valley structure limited by {100} facets, in agreement with the observations [27]. In contact with a solution, at low temperature, the surface vacances on (111), are potential sites of adsorption, two dimensional epitaxy and absorption.…”

Three study cases of growth morphology in minerals: Halite, calcite and gypsum

“…An opposite situation obtains, for the{100} form, where each 100 plane is electrically neutral and hence the potential energy near the {100} surface maintains balanced even for infinite slab extension. Among the ways proposed to cancel out the dipole moment normal to the ideal {111} form, we will confine our attention to the stable {111} surfaces as reconstructed by octopoles, which is by far the most reasonable model [14], since it is the only one for which an experimental evidence was found for the vapor growth [15] and also because this way of reconstructing respects the symmetry of the surface point group. Octopoles are electrically neutral objects lacking dipole moment (Fig.…”

{100} and {111} forms of the NaCl crystals coexisting in growth from pure aqueous solution

“…For the time being, we will confine our attention to the stable {111} surfaces as reconstructed by octopoles [15] which is by far the most reasonable model, being the only one for which an experimental evidence was found for the vapour growth [7]; further, this way of reconstructing takes into account the inner crystal field and, consequently, respects the symmetry of the surface point group. Then, we will use octopoles which are electrically neutral objects lacking dipole moment (Fig.…”

“…During the last four decades many contributions concerned mainly the nature and occurrence of the octahedron (both from vapour and solution growths) that were extensively discussed from the experimental and theoretical point of view [6][7][8][9][10][11][12][13].…”