A crystalline solid of Sn2PO4Cl stoichiometry and orthorhombic structure was characterized and used as electrode material vs. a lithium metal anode. The structure of the solid resembles that of SnO; tin atoms protrude from layers of PO4 tetrahedra, while chlorine atoms are located between Sn layers. Two-electrode electrochemical cells of the type Li/LiClO4(PC:EC)/Sn2PO4Cl (PC, propylene carbonate; EC, ethylene carbonate) were mounted and discharged to a maximum capacity close to 6.4 faradays per Sn atom. This corresponds to the complete reduction of Sn(II) to Sn(0) followed by the formation of noncrystalline Li-Sn alloys up to a limiting composition of Li22Sn5. The second step of the discharge shows an interesting reversibility. After a decrease in capacity during the first ten cycles, ascribable to the increase in the size of tin domains, the charge and discharge capacities remain close to 300 Ah/kg (Sn) up to ra. 40 cycles.