The Li2SiS3 composition was investigated as possible lithium-conducting solid electrolytes. Depending on cooling conditions from the melt, three different phases (equilibrium, metastable crystalline and glass) were formed. The new, metastable crystalline phase had lattice parameters of a = 11.436 angstrom, b = 6.605 angstrom, and c = 6.487 angstrom. The lithium conductivities of the equilibrium, metastable crystalline and glassy phases at room temperature were 2 x 10(-6), 4 x 10(-5) and 1 x 10(-4) (OMEGA cm)-1, respectively. The finding of the metastable crystalline Li2SiS3 and the deduction of its chain structure provided a better idea of the local chain structure of the glassy Li2SiS3.