The present invention relates to a powdered niobium for a capacitor, characterized
in that the content of each of the elements such as iron, nickel, cobalt, silicon,
sodium, potassium and magnesium is about 100 ppm by weight or less or that the
total content thereof is about 350 ppm by weight or less is used, a sintered body
thereof, a sintered body comprising niobium monoxide crystal and/or diniobium mononitride
crystal, a capacitor using the sintered body and the production method of the capacitor.
A capacitor using the above described niobium sintered body has a large capacity
per the unit weight, a good specific leakage current value and excellent high temperature property.
