Electron crystallography of the polymethylene chain. 3. Three-dimensional crystal structure of a refined paraffin wax 1

The three-dimensional crystal structure of a commercial paraffin wax has been determined from electron diffraction intensity data collected from epitaxially oriented samples. The orthorhombic space group is A 2 1 am , where a = 7.46(5) Å, b = 4.97(1) Å, c /2 = 41.2(1) Å. On average, the lamellar packing resembles the B-form of n -C 31 H 64 . Although disorder occurs near the lamellar surfaces, as indicated by fractional atomic occupancies, the final structure ( R = 0.19, based on 38 unique hkl intensities) is still very well-ordered.