Crystal structure of the [(THF)Cs(μ-η(5):η(5)-Cp′)(3)Yb](n) oligomer

The green compound poly[(tetra­hydro­furan)­tris­[μ-η(5):η(5)-1-(tri­methyl­sil­yl)cyclo­penta­dien­yl]caesium(I)ytterbium(II)], [CsYb(C(8)H(13)Si)(3)(C(4)H(8)O)](n) or [(THF)Cs(μ-η(5):η(5)-Cp′)(3)Yb(II)](n) was synthesized by reduction of a red THF solution of (C(5)H(4)SiMe(3))(3)Yb(III) with excess Cs metal and identified by X-ray diffraction. The compound crystallizes as a two-dimensional array of hexa­gons with alternating Cs(I) and Yb(II) ions at the vertices and cyclo­penta­dienyl groups bridging each edge. This, based off the six-electron cyclo­penta­dienyl rings occupying three coordination positions, gives a formally nine-coordinate tris­(cyclo­penta­dien­yl) coordination environment to Yb and the Cs is ten-coordinate due to the three cyclo­penta­dienyl rings and a coordinated mol­ecule of THF. The complex comprises layers of Cs(3)Yb(3) hexa­gons with THF ligands and Me(3)Si groups in between the layers. The Yb—C metrical parameters are consistent with a 4f (14) Yb(II) electron configuration.