Accepted manuscript CrystEngComm. 11 (9) p. 1837-1841 http://pubs.rsc.org/en/content/articlelanding/2009/ce/b905122h Network analysis of bicyclo[3.3.1]nonanes: the diol, the dione and the acetal Carl-Johan Wallentin a , Edvinas Orentas b , Magnus T. Johnson a , Eugenijus Butkus* b , Ola F. Wendt* a , Lars Öhrström* c , and Kenneth Wärnmark* a Received (in XXX, XXX) 1st January 2007, Accepted 1st January 2007 First published on the web 1st January 2007 DOI: 10.1039/b000000x The solid state structure of endo, endo-bicyclo[3.3.1]nonane-2,6-diol, rac-2, shows a hydrogen bonded, three-connected, chiral 3D-net with utg-topology, distinctively different from those formed by the so called tubuland diols, i.e 2,6- dimethylbicyclo[3.3.1]nonane-exo-2, exo-6-diol rac-5, that crystallise as three- connected, chiral eta-nets and from the qtz-net formed by weaker hydrogen bonds in the bicyclo[3.3.1]nonane-2,6-dione, 3. The protected bicyclo[3.3.1]nonane-2,6- dione, bis-2,6-ethylenedioxy acetal 4, has a structure governed by weaker forces and can be interpreted as close packed stacks.