[Ag-12(NPEt3)(8)](3+): A metalla-cryptand filled with a fluoride ion

[Ag12F(NPEt3)(8)] (SiF6)(1,5) (1) was obtained from the reaction of silver( I) fluoride with the silylated phosphaneimine Me3SiNPEt3 in acetonitrile. I t forms colorless, light- and hydrolysis-sensitive crystals, which incorpor ate acetonitrile that is lost in vacuo. 1 .2,3 CH3CN was characterized by i ts IR spectrum and by X-ray crystal structure analysis. Space group Pa (3) over bar, Z = 8, a = 2734.8(1) pm at 153 K, R = 0.059. The compound consist s of cations [Ag12F(NPEt3)(8)](3+) (point group C-3), SiF62- counter-ions a nd acetonitrile molecules which show no interactions. In the cation the sil ver atoms are located on the edges of a nearly undistorted cube and the N a toms of the phosphoraneiminato groups (NPEt3-) occupy the vertices. A fluor ide ion in the center of the cube has contacts of nearly similar length to the 12 silver atoms (mean distance 304.7 pm).