Cs[Cl3F10]: A Propeller‐Shaped [Cl3F10]− Anion in a Peculiar A[5]B[5] Structure Type

Reaction of CsF with ClF₃ leads to CsCl₃F₁₀]. It contains a molecular, propeller‐shaped Cl₃F₁₀]^? anion with a central μ₃‐F atom and three T‐shaped ClF₃ molecules coordinated to it. This anion represents the first example of a heteropolyhalide anion of higher ClF₃ content than ClF₄]^? and is the first Cl‐containing interhalogen species with a μ‐bridging F atom. The chemical bonds to the central μ₃‐F atom are highly ionic and quite weak as the bond lengths within the coordinating XF₃ units (X = Cl, and also calculated for Br, I) are almost unchanged in comparison to free XF₃ molecules. CsCl₃F₁₀] crystallizes in a very rarely observed A^5]B^5] structure type, where cations and anions are each pseudohexagonally close packed, and reside, each with coordination number five, in the trigonal bipyramidal voids of the other.