A crystal structure model of a low-temperature phase II of Ag7Ta6 has been investigated through the Rietveld analysis based on the powder X-ray diffraction intensities measured at 253 K. The structure model proposed has been described in a monoclinic system of a space group Pn With lattice constants A = 7.4530(4), B = 7.4026(4), C = 10.5401(5) Angstrom and beta = 90.069(4)degrees, which is equivalent to a space group Pc with lattice constants A’ = 7.4530(4), B’ = 7.4026(4), C’ = 12.9162(7) Angstrom and beta = 125.310(4)degrees. Seven independent Ag positions are present and they are close to some of the numerous Ag sites of the cubic room-temperature phase. Ag ions seem to form Ag clusters like zigzag-chains, while the argyrodite-type framework TaS6 shows few distortions. A symmetry lowering is considered to arise by transferring of Ag ions from statistical distribution in the room-temperature phase into an ordered arrangement described in the monoclinic system.