  To broaden the scope of van der Waals 2D magnets, we report the synthesis and
magnetism of covalent 2D magnetic Cr$_2$Te$_3$ with a thickness down to
one-unit-cell. The 2D Cr$_2$Te$_3$ crystals exhibit robust ferromagnetism with
a Curie temperature of 180 K, a large perpendicular anisotropy of 7*105 J m-3,
and a high coercivity of ~ 4.6 kG at 20 K. First-principles calculations
further show a transition from canted to collinear ferromagnetism, a transition
from perpendicular to in-plane anisotropy, and emergent half-metallic behavior
in atomically-thin Cr$_2$Te$_3$, suggesting its potential application for
injecting carriers with high spin polarization into spintronic devices.
