Molecular structures in the solid state of [K 2 (dibenzo-18-crown-6)( Dipp NON)CaF 2 ] 2 ( 8 ) ( c ), as determined by X-ray crystallography. The thermal ellipsoids are set at the 30% level. Hydrogen atoms, solvate molecules and second disorder component are omitted, and selected fragments are shown in wireframe format for clarity. Selected bond lengths and angles for 7 : Ca–F 2.097(1) A, K–F 2.434(1) A and Ca–F–K 153.9(1) (for the second molecule in the asymmetric unit: Ca–F 2.100(1) A, K–F 2.425(1) A and Ca–F–K 161.3(1)); and for 8 : Ca–F 2.149(3) and 2.177(3) A, K···F 2.488(3) A, 2.529(3) A, 2.602(3) A, 2.646(3) A and F–Ca–F 91.9(1).