another price explosion for tantalum in 2000/2001 forced the development of niobium electrolytic capacitors with manganese dioxide electrolyte, which have been available since 2002. niobium is a sister metal to tantalum and serves as valve metal generating an oxide layer during anodic oxidation. niobium as raw material is much more abundant in nature than tantalum and is less expensive. it was a question of the availability of the base metal in the late 1960s which led to development and implementation of niobium electrolytic capacitors in the former soviet union instead of tantalum capacitors as in the west. the materials and processes used to produce niobium-dielectric capacitors are essentially the same as for existing tantalum-dielectric capacitors. the characteristics of niobium electrolytic capacitors and tantalum electrolytic capacitors are roughly comparable.