Sulfur-Containing Compound, Solid Electrolyte, and Battery

A sulfur-containing compound containing a lithium (Li) element, a phosphorus (P) element, a sulfur (S) element, and a halogen (X) element, which can be suitably used as a solid electrolyte, and is able to suppress the generation of a hydrogen sulfide gas even when exposed to moisture in the atmosphere. The sulfur-containing compound has a peak at each position of 2θ=21.3°±1.0°, 27.8°±1.0°, and 30.8°±0.5° in an X-ray diffraction pattern measured by an X-ray diffraction apparatus (XRD) using CuKα1 rays.