September 2009 issue
Cover illustration: Memantinium chloride, C12H22N+·Cl- is a medication used to treat dementia caused by Alzheimer's disease. This compound was re-crystrallized as the 0.1-hydrate from an ethanolic solution. The four six-membered rings of the adamantane-like core of the memantinium cation adopt typical chair conformations and are linked with the Cl- counter-anions via N-HCl hydrogen bonds. The disordered crystal lattice water molecules are in the voids of this arrangement and further consolidate the structure by O-HCl hydrogen bonds. See Lou, Hu & Gu [Acta Cryst. (2009). E65, o2191].