Tricyclo-[3.3.1.0]nonane-3,7-diyl bis-(methane-sulfonate).

The crystal structure of the title compound, C(11)H(18)O(6)S(2), was determined to investigate the effect of the eclipsed mesyl groups on the bond length of the vicinal quaternary C atoms. The two quaternary C atoms of the noradamantane skeleton and the two O atoms to which they are connected all located essentially in the same plane [maximum deviation 0.01 Å], resulting in an eclipsing conformation of the C-O bonds. The C-C bond of the quaternary C atoms is 1.597 (3) Å is considerably longer than the other C-C bonds of the mol-ecule.