“…After the successful preparation of single crystals of alkali-biphenyl ion-pairs (Canters, Klaassen & de Boer, 1970), X-ray crystal structure determinations have shown that the structures of aromatic ion-pair containing complexes in the solid state can also be characterized as belonging to the solvent-separated or the contact ion-pair category (Brooks & Stucky, 1972;Brooks, Rhine & Stucky, 1972a,b;Noordik, van den Hark, Mooij & Klaassen, 1974;Noordik, Degens & Mooij, 1975;Goldberg, Raymond, Harmon & Templeton, 1974;Mooij, Klaassen, de Boer, Degens, van den Hark & Noordik, 1976;Noordik, Schreurs, Gould, Mooij & de Boer, 1978). The structures of the paramagnetic complexes rubidium and potassium biphenyl, crystallized from tetraglyme [CH30(CH2CH20)4CHal and having the composition RbBp.2Ttg and KBp.2Ttg (Bp --biphenyl; Ttg = tetraglyme), may be considered to be built up from solvent-separated ion-pairs.…”