It is shown that while none of the E5n (E = Si, Ge, Sn, Pb; n = 0, 2−, 4−) bare clusters can be stabilized in planar pentagon (D5h) geometry, E54− ions as a five-membered planar ring form stable complexes with two {M(CO)3} (M = Cr, Mo, W) metal carbonyls. Interestingly, the negative charge of all [E5{M(CO)3}2]4− complexes is distributed on two {M(CO)3} fragments rather than the coordinated Zintl ion.