  We show that compounds in a family that possess time-reversal symmetry and
share a non-centrosymmetric cubic structure with the space group F-43m (No.
216) host robust ideal Weyl semi-metal fermions with desirable topologically
protected features. The candidates in this family are compounds with different
chemical formulas AB2, ABC, ABC2, and ABCD and their Fermi levels are
predominantly populated by nontrivial Weyl fermions. Symmetry of the system
requires that the Weyl nodes with opposite chirality are well separated in
momentum space. Adjacent Weyl points have the same chirality, thus these Weyl
nodes would not annihilate each other with respect to lattice perturbations. As
Fermi arcs and surface states connect Weyl nodes with opposite chirality, the
large separation of the latter in momentum space guarantees the appearance of
very long arcs and surface states. This work demonstrates the use of system
symmetry by first-principles calculations as a powerful recipe for discovering
new Weyl semi-metals with attractive features whose protected fermions may be
candidates of many applications.
