Crystal structures of complexes between alkali-metal salts and cyclic polyethers. Part IV. The crystal structures of dibenzo-30-crown-10 (2,3:17,18-dibenzo-1,4,7,10,13,16,19,22,25,28-decaoxacyclotriaconta-2,17-diene) and of its complex with potassium iodide

The crystal structures of the title compounds have been determined from X-ray diffractometer observations. The molecules of the cyclic ether are centrosymmetric with Z= 2 in a monoclinic unit cell having a= 16·960, b= 8·920, c= 9·096 Å, β= 90·03°, and space group P21/c. They form loops approximately parallel to the a axis. The structure was solved by the iterative application of Sayres' equation, and refined by least-squares methods to R 0·056 for 1414 independent observations.