Octadecahedral

The ¹¹B spectra of B₁₀H₁₀CN(Me)₃ and the salt Na^⊕[B₁₀H₁₀CH]^⊖ were essentially similar and the structure was rationalized in terms of a “clovo” octadecahedral structure of C₂ᵥ symmetry (65).

Source: wiktionary

Evidence to support an octadecahedral arrangement of boron atoms in [B₁₁H₁₁]²⁻ is provided by structural data for derivatives such as [B₁₁H₁₀(SMe₂)]⁻.

Source: wiktionary

Four highest maxima of the residual electron density map present inside the octadecahedral cages of the framework were assigned to the disordered protonated quinuclidine [9].

Source: wiktionary