  In rare-earth cage compounds, the guest 4f ion cannot be considered as fixed
at the centre of its cage. As result of the electronic degeneracy of the 4f
shell, single-ion or collective mechanisms can redistribute the ion inside the
cage, which can be described in terms of multipolar components. These
mechanisms and their influence are here discussed and illustrated in relation
with the rare-earth hexaboride series. Warning: Following our oral
presentation, this manuscript should have appeared in the Proceedings of SCES
2014 (SCES 2014, International Conference on Strongly Correlated Electron
Systems, held 7 - 11 July 2014 in Grenoble). An infuriated referee decided
otherwise stating, in substance, that "... it could corrupt the youth ... "
(the very few interested in this particular the subject). The casual reader is
here free to appreciate how far this corruption goes...
