Iodine-iodine interactions in dialkyldiiodophosphonium iodides and triiodides

Chain structures of Et2PI5(Et2PI2(super +)I3(super -))(sub x) and t-Bu2PI3(t-Bu2PI2(super +)I(super -))(sub x) are formed due to iodide-iodine interactions of acceptor iodine atoms of dialkyldiiodophosphonium cations, mu(sub 2)-bridging iodide and triiodide anions. Soft-soft interactions of cation-iodide are substantially higher compared to cation-triiodide interactions. The coordination of iodide anions with more acceptor atoms lengthens the I...I contacts.