Abstract: Single crystals of La₆NiSi₂S₁₄ and La₆CoSi₂S₁₄ were obtained by flux growth method at 1100℃.They belong to the hexagonal system, P6₃,a=10.293(1)[10.290(2)]; c=5.774(1) [5.763(2)Å,Z=1 and R=0.036[0.0959] for 627[629] reflections (I≥2.5σ(Ⅰ)).La is 8-coordinated in a distorted dicapped triangular prism with an average La-S distance 2.990[2.992]Å.Ni[Co] (B site) is in a trigonal antiprism of 6S (three Ni[Co]-S have distance of 2.559[2.529] Å and the other three have distance of 2.650[2.679]Å with 1/6 occupancy.Si(C site) is in a tetrahedron and coordinated with S₂ at distance of 2.130[2.146]Å and coordinated with S₃ at 2.098[2.093]Å.