Earth acids

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Earth acids or acidic earth is an outdated name for the oxides of the metals from the vanadium group , i.e. H. of vanadium , niobium and tantalum . The reason for the name is the character of the oxides ( earths ) as acid formers .

Oxides of vanadium are known in the oxidation states + II, + III, + IV and + V: Vanadium (II) oxide VO, vanadium (III) oxide V 2 O 3 , vanadium (IV) oxide VO 2 and vanadium ( V) oxide V 2 O 5 . Oxides of niobium and tantalum were previously in the oxidation states + II, + IV and + V as niobium (II) oxide NbO, niobium (IV) oxide NbO 2 and niobium (V) oxide Nb 2 O 5 or as Tantalum (II) oxide TaO, tantalum (IV) oxide TaO 2 and tantalum (V) oxide Ta 2 O 5 were found.

Individual evidence

  1. ↑ Mineralienatlas , September 13, 2010