The crystal and molecular structure of 2-chlorobicyclo[3,3,1]nonan-9-one

Crystals of 2-chlorobicyclo[3,3,1]nonan-9-one, C9H13CIO, are monoclinic with a= 6·64 A, b= 12·51 A, c= 11·97 A, and β= 118°; the space-group is P21/c and there are four molecules per unit cell. The structure was solved by the heavy-atom method and refined by the method of least-squares. The final value of R over 955 independent reflections was 8·8%. The bicyclo[3,3,1]nonane system of the molecule adopts the twin-chair conformation, and the chlorine atom is in an axial position. Each ring is distinctly flattened and the C(3)⋯ C(7) separation is 3·11 A.