The low-temperature structures of bicyclo[3.3.1]nonan-9-one and 3-azabicyclo[3.2.2]nonane

The ordered, low-temperature structures of two globular bicyclic organic co mpounds have been solved by direct methods and refined at 100 K from powder synchrotron X-ray diffraction data Bicyclo[3.3.1]nonan-9-one, C9H14O, spac e group P2(1)/n, Z = 4, a = 10.4097(3) Angstrom, b = 11.4187(3) Angstrom, c = 6.4964(2) Angstrom, beta = 90.992(1)degrees V = 772.1 Angstrom(3). 3-Aza bidyclo[3.2,2]nonane, C8H15N, space group Aba2, Z = 8, a = 21.1318(5) Angst rom, b = 11.2357(3) Angstrom, c = 6.0863(1) Angstrom, V = 1445 Angstrom(3). Both structures display an efficient packing of molecules held together by intermolecular contacts between hydrogens and the oxygen or nitrogen atom, thus preventing the reorientation of the molecules.