We report here the synthesis and crystal and electronic structures of the Na-2(SC4Nb2)(Nb6O12)(3) niobium oxide whose structure is related to that of Ti2Nb6O12. It constitutes a new member of the larger A(n)BM(6)L(12)(Z) families (A = monovalent cation located in tetrahedral cavities of units, B = monovalent or trivalent cations located in octahedral cavities of units, M = rare earth, Zr, or Nb, Z = interstitial except for M = Nb). The structural relationships between the A(n)BM(6)L(12)(Z) series ((M6L12L6a)-L-i unit-based compounds with a M6Li6L6/2i-aL6/2a-i cluster framework) and Chevrel Phases ((M6L8L6a)-L-i unit-based compounds with a (M6L2L6/2i-aL6/2a- i)-L-i cluster framework) are shown in terms of M6L18 and M6L14 unit packing. Despite a topology similar to that encountered in Chevrel Phases, intercalation properties are not expected in the (Nb6O6O6/2i-aO6/2a-i)-O-i cluster framework-based compounds. Finally, it is shown, from theoretical LMTO calculations, that a semiconducting behavior is expected for a maximum VEC of 14 in the (Nb6O6O6/2i-aO6/2a-i)-O-i cluster framework.