A series of heptametallic cyanide cages are described; they represent soluble analogues of defect-containing cyanometalate solid-state polymers. Reaction of 0.75 equiv of [Cp*Ru(NCMe)(3)]PF6, Et4N-[Cp*Rh(CN)(3)], and 0.25 equiv of CsOTf in MeCN solution produced {Cssubset of[Cp*Rh(CN)(3)](4)[Cp*Ru](3)} (Cssubset ofRh(4)Ru(3)). H-1 and Cs-133 NMR measurements show that Cssubset ofRh(4)Ru(3) exists as a single C-s isomer. In contrast, {Cssubset of[CpCo(CN)(3)](4)[Cp*Ru](3)} (Cssubset ofCo(4)Ru(3)), previously lacking crystallographic characterization, adopts both C-s isomers in solution. In situ ESI-MS studies on the synthesis of Cssubset ofRh(4)Ru(3) revealed two Cs-containing intermediates, Cssubset ofRh(2)Ru(2)(+) (1239 m/z) and Cssubset ofRh(3)Ru(3)(+) (1791 m/z), which underscore the participation of Cs+ in the mechanism of cage formation. Cs-133 NMR shifts for the cages correlated with the number of CN groups bound to Cs+: Cssubset ofCo(4)Ru(4)(+) (delta 1 vs delta 34 for CsOTf), Cssubset ofRh(4)Ru(3) where Cs+ is surrounded by ten CN ligands (delta 91), Cssubset ofCo(4)Ru(3), which consists of isomers with 11 and 10 pi-bonded CNs (delta 42 and delta 89, respectively). Although {Ksubset of[Cp*Rh(CN)(3)](4)[Cp*Ru](3)} could not be prepared, {NH(4)subset of-[Cp*Rh(CN)(3)](4)[Cp*Ru](3)} (NH(4)subset ofRh(4)Ru(3)) forms readily by NH4+-template cage assembly. IR and NMR measurements indicate that NH4+ binding is weak and that the site symmetry is low. CsOTf quantitatively and rapidly converts NH(4)subset ofRh(4)Ru(3) into Cssubset ofRh(4)Ru(3), demonstrating the kinetic advantages of the M-7 cages as ion receptors. Crystallographic characterization Of CsCo4Ru3 revealed that it crystallizes in the C-s-(exo)(1)(endo)(2) isomer. In addition to the nine mu-CN ligands, two CNt ligands are pi-bonded to Cs+. Msubset ofRh(4)Ru(3) (M = NH4, Cs) crystallizes as the second C-s isomer, that is, (exo)(2)(endo)(1), wherein only one CNt ligand interacts with the included cation. The distorted framework of NH(4)subset ofRh(4)Ru(3) reflects the smaller ionic radius of NH4+. The protons of NH4+ were located crystallographically, allowing precise determination of the novel NH4...CN interaction. A competition experiment between calix[4]arene-bis(benzocrown-6) and NH(4)subset ofRh(4)Ru(3) reveals NH(4)subset ofRh(4)Ru(3) has a higher affinity for cesium.