In the title compound, 2,3-diethoxy-1-(1,10-phenanthroline-N, N')-1-ruthena
-closo-undecaborane, [RU(C4H18B10O2)(C12H8N2)], the Ru atom is bound to two
N atoms of the 1,10-phenanthroline (phen) ligand and six B atoms of the cl
oso 11-vertex {RuB10} cage. The Ru-N bond distances are 2.117(2) and 2.128(
2) Angstrom, and the N1-Ru1-N10 bite angle is 78.26(8)degrees.