ium j Azide/ Crystal structure Abstract. The crystal structure of the title compound was determined by single crystal x-ray diffraction. The crystals are triclinic, α = 9.338(1), b = 10.786(3), c = 11.684(2) A, a = 92.59(l)°, 0 = 107.86(1)°, y = 113.69(1)°, space group Pi, Z=l, dx = 2.84Mgm"3. The structure was solved by Patterson and Fourier methods and refined to a conventional R=0.041 for 3101 independent ΜοΛΓα counter reflections. Calcium is coordinated to seven azide groups, the coordination polyhedra are distorted pentagonal bipyramids. Pairs of them are related by a center of symmetry and share a common edge. The cesium ions are irregulary surrounded by azide-groups.