M(CN)(2) SPECIES (M=BE, MG, CA, SR, BA) - CYANIDES, NITRILES, OR NEITHER

The ''cyanide'' salts of the group 2 (alkaline earth) metals exhibit r emarkable structural variations: CN- binds to the metals via the carbo n, via the nitrogen, and via bridged arrangements. The most stable geo metries of the beryllium and the magnesium salts are linear (CNBeNC an d NCMgCN, respectively), but CaC2N2, SrC2N2, and BaC2N2 prefer twisted , bridged structures. However, several stationary points of the bridge d complexes are close in energy, and considerable fluxionality is to b e expected. These theoretical predictions (MP4SDTQ/6-311+G(2d)/MP2(fu) /6-31+G, Ca, Sr, Ba: 5s5p3d1f//5s5p3d basis sets and 10 valence elect ron pseudopotentials) invite experimental verification.