_Columbium trichloride_, CbCl3, is obtained in needles or crystalline crusts, when the vapour of the pentachloride is slowly passed through a red-hot tube. When heated in a current of carbon dioxide it forms the oxychloride CbOCl3, and carbon monoxide. _Columbium pentachloride_, CbCl5, is obtained in yellow needles when a mixture of the pentoxide and sugar charcoal is heated in a current of air-free chlorine. It melts at 194° C. (H. Deville) and boils at 240.5° C. It is decomposed by water, and dissolves in hydrochloric acid. _Columbium oxychloride_, CbOCl3, is formed when carbon tetrachloride, and columbic acid are heated together at 440° C.: 3CCl4 + Cb2O5 = 2CbOCl3 + 3COCl2, and also by distilling the pentachloride, in a current of carbon dioxide, over ignited columbic acid. It forms a white silky mass which volatilizes at about 400° C. It deliquesces in moist air, and is decomposed violently by water. _Columbium pentafluoride_, CbF5, is obtained when the pentoxide is dissolved in hydrofluoric acid. It is only known in solution; evaporation of the solution yields the pentoxide. The _oxyfluoride_, CbOF3, results when a mixture of the pentoxide and fluorspar is heated in a current of hydrochloric acid. It forms many double salts with other metallic fluorides. Entry: COLUMBIUM