The New International Encyclopædia/Columbium

COLUM′BIUM (Neo-Lat., from Columbia, United States of America) or Niobium. A metallic element discovered by Rose in 1846. It is found in the minerals columbite, from Haddam and Middletown, Conn., and tantalite, from near Falun and elsewhere in Sweden; also in small quantities in other minerals. In order to obtain the element the mineral is fused with acid potassium sulphate; the resulting mass, which is washed and boiled with concentrated hydrochloric acid, yields the hydroxide, which is then reduced. Columbium (symbol Cb or Nb, atomic weight 94) is a steel-gray powder with a specific gravity of 7.06. It forms three oxides with oxygen, of which the pentoxide, Cb₂O₅, forms salts called columbates or niobates.