  Using the accurate first-principle method within density-functional theory,
we systematically study CrSb in the zincblende (zb) structure. The zb CrSb is
predicted of robust half-metallic ferromagnetism (HMFM) with a magnetic moment
of 3.000 $\mu_B$ per formula. It is much better than other zb compounds with
HMFM because its spin-flip gap reaches 0.774 eV at the equilibrium volume and
persists nonzero with its volume changing theoretically from -21% to +60%. It
is found there may be a common mechanism for the HMFM in all the zb Cr- and
Mn-pnictides. Since being compatible with the III-V semiconductors, this
excellent HMFM of the zb CrSb should be useful in spin electronics and other
applications.
