Constitution of Calycanine

Abstract

SOME time ago, on the suggestion of Prof. A. R. Todd, calycanine was examined by X-ray methods^1,2 in order to decide whether a constitution originally suggested by Barger, Madinaveitia and Strouli³ for a molecule C₁₆H₁₀N₂ is in harmony with the crystallographic symmetry and the unit cell dimensions. That investigation established the approximate dimensions of a monoclinic unit cell as a = 13.7 A., b = 4.45 A., c = 9.7 A., Î = 107°, and showed that the space group is P2_1/a — C_2h⁵, provided that a few very weak reflexions are neglected. If these reflexions are taken into account, it was suggested that the above cell should be regarded as a pseudo-cell, the true unit cell having a doubled c-axis, 2 × 9.7 A. Fairly detailed suggestions were advanced as to the probable crystal structure, but the chemical synthesis which Prof. A. R. Todd intended to carry out has not been completed because of the War.