The cationic cages nido-[C2But2P2E]+ (E = As, Sb), which are isolobal to the cyclopentadienyl cation, adopt square based pyramidal structures with the heavy pnictogen atom at the apex; NMR and computational methods have been used to probe the dynamic behaviour of the complexes.
Bibliographical notePublisher: Royal Society of Chemistry
Fish, C., Green, M., Jeffery, JC., Kilby, RJ., Lynam, JM., McGrady, JE., Pantazis, DA., Russell, CA., & Willans, CE. (2006). Cationic phosphorus-carbon-pnictogen cages isolobal to [C5R5]+. Chemical Communications, 13, 1375 - 1377. https://doi.org/10.1039/b517710c