Chemically related to vanadium are the two elements tantalum and columbium or niobium.
COLUMBIUM, or Niobium (symbol Cb or Nb, atomic weight 94), one of the metallic elements of the nitrogen group, first detected in 1801 by C. Hatchett in a specimen of columbite (niobite) from Massachusetts (Phil.
Columbium compounds are usually prepared by fusing columbite with an excess of acid potassium sulphate, boiling out the fused mass with much water, and removing tin and tungsten from the residue by digestion with ammonium sulphide, any iron present being simultaneously converted into ferrous sulphide.
It is then dissolved in hydrofluoric acid and heated in order to expel silicon fluoride; finally the columbium, tantalum and titanium fluorides are separated by the different solubilities of their double fluorides (C. Marignac, Ann.
Columbium hydride, CbH, is obtained as a greyish metallic powder, when the double fluoride, CbF 5, 2 KF, is reduced with sodium.
Three oxides of columbium are certainly known, namely the dioxide, Cb202, the tetroxide, Cb 2 0 4, and the pentoxide, Cb 2 0 5, whilst a fourth oxide, columbium trioxide, Cb203, has been described by E.
Columbium dioxide, Cb202, is formed when dry potassium columbium oxyfluoride is reduced by sodium (H.
Columbium Crystal of Columbite.
Columbium trichloride, CbC1 3, is obtained in needles or crystalline crusts, when the vapour of the pentachloride is slowly passed through a red-hot tube.
Columbium pentachloride, CbC1 5, is obtained in yellow needles when a mixture of the pentoxide and sugar charcoal is heated in a current of air-free chlorine.
Columbium oxychloride, CbOC1 3r is formed when carbon tetrachloride, and columbic acid are heated together at 440° C.: 3CC14+Cb205 = 2CbOC1 3 +30001 2, and also by distilling the pentachloride,in acurrent of carbon dioxide, over ignited columbic acid.
Columbium pentafluoride, CbF5, is obtained when the pentoxide is dissolved in hydrofluoric acid.
Columbium oxysulphide, CbOS 3, is obtained as a dark bronze coloured powder when the pentoxide is heated to a white heat in a current of carbon bisulphide vapour; or by gently heating the oxychloride in a current of sulphuretted hydrogen.
A heavy white precipitate, consisting of ammonium chloride and columbium nitride, is thrown down, and the ammonium chloride is removed by washing it out with hot water, when the columbium nitride remains as an amorphous residue (Hall and Smith, loc. cit.).
Potassium fluoxy percolumbate, K2Cb02F5 H20, is prepared by dissolving potassium columbium oxyfluoride in a 3 ° solution of hydrogen peroxide.
1866 (4), 8, p. 16) to be 94 from the analysis of potassium columbium oxyfluoride, and the same value has been obtained by T.
In 1809 he proved the elementary character of columbium (niobium) and titanium.
Of minerals containing this element mention may be made of cassiterite or tinstone, Sn02, tin pyrites, Cu 4 SnS 4 + (Fe,Zn) 2 SnS 4; the metal also occurs in some epidotes, and in company with columbium, tantalum and other metals.
In 1801 C. Hatchett detected a new element, which he named columbium, in a mineral from Massachusetts, and in 1802 A.
Wollaston unsuccessfully endeavoured to show that columbium and tantalum were identical.
Blomstrand, and others, especially of Marignac, proved the identity of columbium, dianium and niobium, and that ilmenium was a mixture of columbium and tantalum.
In its chemical relationships tantalum is associated with vanadium, columbium and didymium in a sub-group of the periodic classification.
Its double salts with the alkaline fluorides are very important, and serve for the separation of the metal from columbium and titanium.