Cyclopentadienylcaesium by High-Resolution X-ray Powder Diffraction

The structure of solid (η⁵-cyclopentadienyl)caesium, [CsC₅H₅], has been refined by high-resolution powder X-ray diffraction. Atomic parameters based on the isostructural Rb analogue were used in the starting model. The compound crystallizes in the space group Pnma with Z = 4 and unit-cell parameters a = 11.3664 (2), b = 8.8648 (2) and c = 5.7200 (1) Å. [Cs(C₅H₅)] shows a polymeric zigzag chain, a so-called multidecker structure, with an average Cs—Cp_centroid distance of 3.140 (5) Å. [Cs(C₅H₅)] contains a single chain along the a axis. The chains are bent with a Cp_centroid—Cs—Cp_centroid angle of 129.7 (1)°.

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