A single-crystal rod with a composition of Li6.95La3Zr1.95Nb0.05O12 was grown using the floating zone method. The single-crystal rod had a diameter of 8 mm and length of 90 mm. Li6.95La3Zr1.95Nb0.05O12 crystallizes in an orthorhombic system, with space group Ibca, and the single crystal with 0.05 substitutions of niobium had the following lattice parameters: a = 13.1280(3) angstrom, b = 12.6777(3) angstrom, and c = 13.1226(4) angstrom. The reliability values obtained were R = 1.77% and wR = 3.27% in Li6.95La3Zr1.95Nb0.05O12 for 857 independent refractions, with a shift/error for 115 parameters of less than 0.001 value in the single-crystal X-ray diffraction data. Four interspace sites were occupied by the Li ions, constructed by the framework structure. The Li1, Li2, and Li3 ions are located in the octahedral 16f site, and Li4 is in the tetrahedral 8d site. The bulk lithium-ion conductivity in Li6.95La3Zr1.95Nb0.05O12 was 3.21 x 10(-4) S cm(-1) at 298 K.