Anisotropy Analysis of the Mechanical Property of K_1–x A _x DP Crystals by the Oriented Distribution of Chemical Bond

We have proposed an approach to characterize the anisotropy of mechanical property in K_1–x A _x DP crystallographic frame by the oriented distribution of chemical bond. The anisotropic hardness of K_1–x A _x DP crystals and their dependence on constituent concentration were quantitatively calculated. The hardness of K_1–x A _x DP decreases with increasing NH⁺ ₄ concentration x. The detailed variation of chemical strain in the whole composition range was determined. The chemical strain along c-axis quickly accumulates with increasing the content of NH⁺ ₄ and reaches the biggest when x approaches to 0.6. The current work indicates that the oriented distribution of bond valence captures the main interaction of crystal materials and can be utilized for the description of crystal anisotropy.