Crystal and molecular structure of potassium hydrogen norborn-5-ene-2-endo,3-endo-dicarboxylate sesquihydrate, C9H9KO4,1.5H2O

Abstract

The crystal and molecular structure of the title compound has been determined by X-ray diffraction from 830 visually estimated intensities. The structure was refined by block-diagonal least squares to R 0.117. The nucleus of the molecule consists of norbornene with a basket-shaped skeleton. The carboxy-groups are joined to the single-bond carbon atoms at the bottom of the basket-shaped carbocyclic ring. The structure is built up of two-dimensional layers parallel to the (100) plane. Each layer consists of a two-dimensional network of cornersharing K⁺ polyhedra covered on both sides by the norbornene molecules which are joined to the polyhedra by the carboxy-oxygens and to each other, through the layer, by hydrogen bonds. The tightly bonded layers are held together by van der Waals forces. Crystals are orthorhombic, space group Ccc2, with Z= 8 in a unit cell of dimensions: a= 25.24(9), b= 10.18(5). and c= 8.27(4)Å.