COLUMBIUM

(Chemical Symbol Cb) – Element No.41 of the periodic system. Atomic weight 92.91. It is steel gray in color and brilliant luster. Specific gravity 8.57. Melting point at about 43790 F. It is used mainly in the production of stabilized austenitic chromium-nickel steels, also to reduce the air-hardening characteristics in plain chromium steels of the corrosion resistant type. (Now known as Niobium (Nb), Element No. 41 of the periodic system.)