The cluster compound Hg3(mu-dppm)3(SO4)2 (dppm = diphenylphosphinometh
ane) which contains the triangular Hg-3(4+) moiety shows an intense lo
w-temperature (77 K) photoluminescence at lambda(max) = 658 nm. This e
mission is assumed to originate from a metal-centered ss excited state
which undergoes a Jahn-Teller distortion.