  A broad extension of periodic system into the sector of antimatter could be
possible sometimes in a remote future. We expect that anti-alpha spontaneous
emission from an antimatter nucleus will have the same Q-value and half-life as
alpha emission from the corresponding mirror nucleus. This is the consequence
of the invariance of binding energy as well as of the surface and Coulomb
energy when passing from matter to antimatter nuclei with the the same mass
number and the same atomic number. The Q-values and half-lives of all measured
up to now 27 cluster radioactivities are given together with Q-values and
half-lives of the most important competitor --- $\alpha$ decay. The lightest
anti-alpha emitter, $^8\bar{Be}$, will have a very short half-life of about
$81.9\cdot 10^{-18}$ s.
