Structures of two binary n-alkane solid solutions

From X-ray diffractometer single-crystal data, the structures of two binary n-alkane phases have been determined. (1) β-C 24 H 50 , C 26 H 54 , β-tetracosane-hexacosane, mole fraction of C 24 H 50 0.77, hence effective molecular weight 345. 39, space group Bb2 1 m (No. 36), a=4.992 (1), b=7.503 (3), c=67.448 (8) A, Z=4, D x =0.91 g cm -3 , 201 significant reflections out of 588, R=0.11 and wR=0.09. The structural motif gives an n-alkane backbone 27 carbons long with C-atom sites well resolved on the F map. The outer three C-atom sites at each end of the motif have occupancies less than unity