Heteroborane

Heteroboranes are classes of boranes in which at least one boron atom is replaced by another element. Like many of the related boranes, these clusters are polyhedra and are similarly classified as closo-, nido-, arachno-, and hypho-, according to the so-called electron count. Closo- represents a complete polyhedron, while nido-, arachno- and hypho- stand for polyhedrons that are missing one, two and three vertices.

Structurally, various heteroboranes can be derived from the icosahedral (I_h) B₁₂H₁₂^2– via formal replacement of its BH fragments with isoelectronic CH⁺, P⁺ or S²⁺ fragments, e.g. closo-1-CB₁₁H₁₂^–, closo-1,2-C₂B₁₀H₁₂, closo-1,2-P₂B₁₀H₁₀ or closo-1-SB₁₁H₁₁.