Crystal structure of exo-tricyclo[3,2,1,02,4]oct-6-ene–silver nitrate, and a refinement of the silver nitrate structure

Abstract

Crystals of exo-tricyclo[3,2,1,02,4]oct-6-ene-silver nitrate are orthorhombic, a= 25·54, b= 6·28, c= 5·60 A, Z= 4, space group P212121. The structure was determined with Mo-Kα diffractometer data from Patterson and electron-density maps and was refined by least-squares methods to a final R of 0·105 for 322 observed reflexions. The structure contains thick layers perpendicular to a and separated by ½a; within the layers each silver ion is coordinated roughly tetrahedrally to the double bond of the hydrocarbon (in the exo-position, Ag ⋯ C 2·4 A), and to three nitrate groups (Ag ⋯ O 2·45–3·03 A). The layers are held together by van der Waals forces.The structure of silver nitrate was refined with Mo-Kα diffractometer data to R 0·067 for 404 observed reflexions. Previously observed inequalities in N–O distances have been removed, all three bond lengths in the nitrate ion being 1·26(1)A.