Niobium monoxide
Niobium monoxide
Black odorless solid
Fixed
7.3 g · cm -3
1945 ° C
- Slightly soluble in hydrochloric acid
- Insoluble in nitric acid
Attention
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Niobium ( II) oxide is a chemical compound of niobium and oxygen. The gray solid is next niobium (V ) oxide and niobium ( IV) oxide is one of more stable oxides of niobium. In contrast to the other niobium oxides, the compound is electrically conductive ( about 106 S / cm) and is used as an anode material in electrolytic capacitors niobium.
Production and representation
Niobium ( II) oxide can be prepared by reacting with elemental niobium niobium oxides at high temperatures. The exact ratio of the reactants depends on the oxide used.
Properties
Niobium ( II) oxide has an unusual crystal structure. This can be described as a derivable from the sodium chloride structure ordered defect structure. Six niobium atoms thereby form an octahedral cluster with the otherwise present in the sodium chloride structure central anion is absent. At the same time lacks the niobium atoms in the corners of the unit cell.
Within the metal cluster are niobium -niobium bonds ago with a bond length of 298 pm. These are in their length where the elemental niobium very similar ( Nb Nb: 285 pm ), and cause the metallic properties of niobium (II ) oxide.
Use
Niobium ( II) oxide is used as anode material in the niobium electrolytic capacitors. They play as the corresponding tantalum capacitors play an important role in microelectronics, for example, in laptops. Compared to tantalum capacitors they are cheaper, but can not withstand such high voltages. Another advantage of niobium (II ) oxide is the higher temperature stability as compared to tantalum.
Other applications are to be protected against corrosion in seawater coating by grounding electrodes of high-voltage direct current transmission ( HVDC) as the HVDC Italy - Greece to the grounding electrode ( anode).