NOVELTY - Thermoelectric material comprises metallic compound (I).    USE - The thermoelectric material is useful: in thermoelectric element for thermoelectric module and thermoelectric device (all claimed); and for thermoelectric cooling system, micro-cooling system, cooling device for commercial or residential use, air conditioners, thermoelectric power generation system, waste heat power generation system, non-refrigerant refrigerators, and thermoelectric nuclear power generation for military and aerospace purposes.    ADVANTAGE - The Thermoelectric material has: high thermoelectric figure-of-merit and large Seebeck coefficient; high electrical conductivity and low thermal conductivity; and improved mechanical strength and high thermoelectric performance.    DETAILED DESCRIPTION - Thermoelectric material comprises metallic compound of formula ((A1)a(R1)b(G1)3 plus minus n) (I).    A1 = at least one element including group 1 element, group 2 element or metal of groups 3-12;    R1 = rare-earth element;    G1 = at least one element including sulfur, selenium, tellurium, phosphorus, arsenic, antimony, bismuth, carbon, silicon, germanium, tin, boron, aluminum, gallium or indium;    a, b = less than 0 to greater than or equal to 1; and    n = greater than or equal to 0 to less than 1.    INDEPENDENT CLAIMS are also included for:    (1) a thermoelectric module comprising a first electrode, a second electrode, and a thermoelectric element interposed between the first electrode and the second electrode, where the thermoelectric element comprises the thermoelectric material; and    (2) a thermoelectric device comprising a heat source, and a thermoelectric module including a thermoelectric element, which absorbs heat from the heat source, a first electrode which contacts the thermoelectric element and a second electrode, which faces the first electrode and contacts the thermoelectric element.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic view illustrating thermoelectric cooling by the Peltier effect.