The compound Nb4O4(OAc)(4)(OPri)(8) synthesized by reacting Nb(OPri)(5) and acetic acid has been fully characterized by single-crystal X-ray diffraction (a = 11,634(5) Angstrom, b = 14,370(6) Angstrom, c = 16,380(6) Angstrom, alpha = 79.90(4)degrees, beta = 71.78(4)degrees, gamma = 79.21(4)degrees, triclinic, P (1) over bar, Z = 2) and multinuclear NMR experiments performed in the solid state and in solution. A simple possible mechanism that can account for its formation is presented. C-13 CP MAS experiments, using the IRCP sequence (inversion recovery cross polarization), are used to perform straightforward assignments of the resonances of the different isopropoxy ligands bonded to niobum. O-17, C-13 and H-1 NMR spectroscopies show that the cluster structure is fully preserved in solution.