Die Kristallstruktur von Cycloalkanen

Abstract

An X-ray structure analysis was performed on single crystals of the cycloalkane (CH2)36. The lattice belongs to the space group Aa and is arranged in layers. The unit cell has the dimensions = 1,033 nm, b = 0,824 nm, c = 4,22 nm, = 107, 1° and contains four molecules. The molecules consist of two stretched stems which are linked by sharp folds at each end. The folds have the conformation t(g g t g g) t lying parallel to the b-axis. Raman measurements suggest that the stems are slightly twisted. A comparison of the homologous series (CH2)n, n = 36, 48, 60, and 72 using X-ray powder methods showed that the (CH2)36-structure, including the fold conformation, is also representative for the longer chain cycloalkanes.