Standard triangle
In crystallography , solid state and material physics, the expression standard triangle denotes the spherical triangle ( spherical triangle ) that is spanned by the direction vectors <100>, <110> and <111>.
The standard triangle describes the 8th part of the entire surface of the sphere. Due to the symmetry properties of many crystal structures , these properties can be described for all spatial directions by describing direction-dependent properties within the standard triangle. Typical corresponding crystal structures are cubic-primitive , cubic space-centered and cubic face-centered crystal lattices. The representation of the standard triangle is used. a. when describing direction-dependent (anisotropic) stress / strain behavior , transport properties (e.g. diffusion , conductance ) and structure ( structure ).