From Fig. , we see that as the chiral angle approaches higher degree values, the strength of the material increases. We explain the trend as when the uniaxial strain angle approaches 90 • , the nonplanar P-P bonds become more perpendicular to the direction of applied strain. With such, these nonplanar bonds experience less direct loading from the strain. Comparatively, when the angle is low, the nonplanar P-P bonds are more aligned parallel to the loading direction. Since these bonds have a larger z component perpendicular to the overall plane of the phosphorene layer, they easily straighten to deform, resulting in lower strengths. There is no distinct correlation between stiffness and angle.