In organometallic chemistry, a dicarbollide is an anion of the formula [CBH].  Various isomers exist, but most common is 1,2-dicarbollide derived from ortho-carborane.  These dianions function as ligands, related to the cyclopentadienyl anion.  Substituted dicarbollides are also known such as [CBH(pyridine)] (pyridine bonded to B) and [CRBH] (R groups bonded to carbon).