(cAAC)Ge(GeL)2 (1) (cAAC = cyclic alkyl(amino) carbene; L = PhC(tBuN)2), a functionalized Ge3-compound was prepared. Quantum mechanical studies on 1 show a reciprocal relationship between the electronic state of the central tri-coordinated Ge atom and its reactivity towards protons, viz. tetravalent Ge(0) in terms of bonding and divalent Ge(0) in terms of reactivity. Thus the central Ge atom can be considered as having a hidden but highly reactive lone pair of electrons. However, the terminal Ge atoms can be considered as tri-coordinated divalent Ge(i) with an active lone pair of electrons. © 2014 Royal Society of Chemistry.