The metallaboranes (CpM)(2)BnHn+4 (M = Cr, Mo, W; n = 4, 5; Cp = eta (5)-C5H5, eta (5)-C5Me5), (CPW)(2)B7H9 (CPRe)(2)B7H7, and (CpW)(3)B8H9 have the 2v or 2v + 2 skeletal electrons for close or isoclose deltahedra (v number of polyhedral vertices) if the early transition metal vertices are assumed to contribute four or more internal orbitals rather than the usual three internal orbitals for BH vertices. The polyhedra for the metallaboranes (CpM)(2)BnHn+4 (M = Cr, Mo, W; n = 4, 5) are derived from (n + 1)-gonal bipyramids by removal of an equatorial vertex. The deltahedra for the larger metallaboranes (CpW)(2)B7H7, (CpRe)(2)B7H7, and (CpW)(3)B8H9 are derived from the corresponding BnHn2- deltahedra (n = 9 and 11 in these cases) by sufficient diamond-square-diamond processes to provide vertices of degrees greater than or equal to 6 for each of the CpM vertices. Reasonable skeletal bonding topologies in accord with the availability of skeletal electrons and orbitals consist of surface 2c-2e and 3c-2e bonds supplemented by metal-metal bonding through the center of the polyhedron.