  We derive a realistic spin-orbital model at finite Hund's exchange for alkali
hyperoxides. We find that, due to the geometric frustration of the oxygen
lattice, spin and orbital waves destabilize both spin and p-orbital order in
almost all potential ground states. We show that the orbital order induced by
the lattice overrules the one favoured by superexchange and that this, together
with the large interorbital hopping, leads to generalized Goodenough-Kanamori
rules. They (i) lift the geometric frustration of the lattice, and (ii) explain
the observed layered C-type antiferromagnetic order in alkali hyperoxides. This
is confirmed by a spin-wave dispersion with no soft-mode behavior presented
here as a prediction for future experiments.
