Abstract. K2(CsHs).(CH3OCH2CH2)20, (K2COT.diglyme), orthorhombic, Pnma, a = 7.689 (3), b = 15.376 (5), c= 13.703 (5) A (from diffractometer data), Z=4, Dx= 1.30 g cm -3. The packing of the K + and COT 2-ions may be described as a zigzag chain of K2COT units. This chain is in the direction of the a axis and is embedded in a diglyme environment. Only one potassium ion of each K2COT unit is coordinated by the complexing ether, diglyme.Introduction. The crystals were prepared under exclusion of air and water by slowly adding a mixture of diglyme and tetrahydrofuran (THF) (1:2) to a 0.8 mol K2COT solution in THF. After one day single crystals separated out. The results of an elementary analysis are K, 24"60 (24"71), C, 52"82 (53.12) and H, 7.07 (7-01)%. (Values in parentheses are the calculated ones.) The crystals are very sensitive to air. Therefore they were mounted in paraffin (m.p. 42-44°C) in thin-walled glass capillaries under a He atmosphere. Unit-cell dimensions and intensities were obtained from a crystal of approximate dimensions 0.4 × 0-3 × 0.2 ram, with a computer-controlled Nonius CAD-3 diffractometer (Cu Ks radiation, Ni-filtered, 0-20 scan). Systematic

In press. (23) J.

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NMR experiments on sodium biphenyl (NaBp), potassium biphenyl (KBp) and ribidium biphenyl (RbBp), dissolved in various solvents are summarized with emphasis on the structural information which can be obtained from such experiments. The crystal structures of NaBp.2Tg (Tg = triglyme), KBp.2Ttg and RbBp.2Ttg (Ttg tetraglyme) are discussed, in relation to the NMR results obtained for these systems in solution. In the solid state these crystals may be considered to be built up of solvent separated ion pairs. Magnetic experiments are reported for single crystals of the three systems. Susceptibility measurements revealed a ferromagnetic coupling in NaBp.2Tg and KBp.2Ttg and an antiferromagnetic coupling in RbBp.2Ttg. All crystals exhibit an exchange narrowed ESR line, with an orientation dependent linewidth. From the resonance positions the molecular g tensor of the biphenyl anion could be derived. The orientation dependent linewidth is due to dipolar interactions between the spins. A quantitative explanation of it could not be given at present.

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