Coordination polyhedron growth mechanism model and growth habit of crystals

A new growth mechanism model, coordination polyhedron growth mechanism model, is introduced from the angle of the coordination of anion and cation to each other at the interface. It is pointed out that the force driving the growth unit to enter the crystal lattice is the electrostatic attraction force between ions, whose relative size can be approximately measured by the electrostatic bond strength (EBS) that reaches a nearest neighbor anion (or cation) in the parent phase from a cation (or anion) at the interface. The growth habits of NaCI, ZnS, CaF2 and Csl crystals are discussed, and a new growth habit rule is proposed as follows. When the growth rate of a crystal is determined by the step generation rate, the growth habit of this crystal is related to the coordination number of the ion with the smallest coordination rate at the interface of various crystal faces. The smaller the coordination number of the ion at the interface, the faster the growth rate of corresponding crystal face. When the growth of a crystal depends on the step movement rate, the growth habit of this crystal is related to the density of the ion with the smallest coordination rate at the interface of various crystal faces. The smaller the densities of the ion at the interface is, the faster the growth rate of corresponding crystal face will be.