Crystal Structure of Cesium Phenylacetylide, CsC 2 C 6 H 5 , Solved and Refined from Synchrotron Powder Diffraction Data

The crystal structure of cesium phenylacetylide, CsC 2 C 6 H 5 , was solved and refined from synchrotron powder diffraction data ( Pbca , Z = 8). Each Cs + cation is coordinated by five ligands: four acetylide groups coordinate side‐on and one end‐on. A similar arrangement is found in the crystal structure of NaC 2 H ( P 4/ nmm , Z = 2). There is a group‐subgroup relationship between both structures. Most importantly, the crystal structure of CsC 2 C 6 H 5 could only be solved with the help of synchrotron data, as the very good peak:noise ratio allowed the assignment of several very weak reflections, which finally led to the correct space group, in which a structural solution was possible using direct space methods.