1-Nitronaphthalene, a non-OD, non-MDO polytype

Abstract Crystals of 1-nitronaphthalene were grown by evaporation of a methanol solution. The structure P 2 1 / c , a = 13.2780(13) Å, b = 3.8131(3)° Å, c = 31.851(3) Å, β = 91.173(8), V = 1,612.3 Å 3 was solved from a crystal twinned by twofold rotation about 100. Twinning is explained by the polytype character: layers with (idealized) p 2 1 11 symmetry can connect via either 1‾ or 2 1 operations, leading to geometrically distinct pairs of layers. In the twin individuals, the two kinds of contacts alternate, at the composition plane two subsequent contacts of the same type are realized.