Abstract 9,10-Phenanthrenequinone (PQ) derivatives of vanadium, niobium and tantalum of formula V(C 14H 8O 2) 3] (M = V, Nb, Ta) have been prepared: (a) by reaction with PQ of the carbonyl derivatives V(CO) 6 and Na[M(CO) 6] (M = V, Nb, Ta) and (b) by reaction of the anhydrous metal chlorides VCl 3 and M 2Cl 10 (M = Nb, Ta) with the mono- or the di-anion of PQ. Reaction of Na[M(C 14H 8O 2) 3] (M Nb, Ta) with hydrogen chloride has given the protonated species H[M(C 14H 8O 2) 3] in good yields. Treatment of V(C 14H 8O 2) 3 or Na[V(C 14H 8O 2) 3] with sodium sand in THF gave the reduced derivatives of formula Na n [V(C 14H 8O 2) 3] ( n = 1, 2, 3) which were isolated and identified by elemental analysis and IR spectroscopy. Oxidation of the anionic species by silver ions was examined. The reduced species Na 3[M(C 14H 8O 2) 3] (M = V, Nb, Ta) react with benzyl chloride or triphenylmethylchloride in THF to give dibenzyl and hexaphenylethane, respectively.