Direction cosines and bond angles in a diamond lattice

[FRANCLI]

hello
how can I find the angles between the tetahedral bonds of a diamond lattice & what are the direction cosines of the nearest-neighbor bonds with the atom at the origin along the x, y, z axes ?

 

[tiny-tim]

Hello FRANCLI!

hello
how can I find the angles between the tetahedral bonds of a diamond lattice & what are the direction cosines of the nearest-neighbor bonds with the atom at the origin along the x, y, z axes ?

What is the definition of tetrahedral?

What have you tried so far?