For the first time the 6I emission of Eu2+ is reported. 6I emission of
Eu2+ in KMgF3 can be observed because the energetically lowest 4f(6)5
d state is situated above the I-6(7/2) state of Eu2+. This high energe
tic position of the lowest 4f(6)5d state of Eu2+ in KMgF3 is explained
by the small crystal-field splitting and the high position of the cen
tre of gravity of the 4f(6)5d states. The decay time of the 6I emissio
n at 4.2 K is 96 mus. Above 25 K the 6I emission is completely quenche
d via the lowest 4f6 5d state, which is at some 50 cm-1 above the I-6(
7/2) levels.