Niobium (II) oxide

Structural formula
General
Surname	Niobium (II) oxide
other names	Niobium monoxide
Molecular formula	NbO
Brief description	black odorless solid
External identifiers / databases
EC number	234-808-1
ECHA InfoCard	100,031,631
PubChem	82838
Wikidata	Q408445
properties
Molar mass	108.9 g mol −1
Physical state	firmly
density	7.3 g cm −3
Melting point	1945 ° C
solubility	somewhat soluble in hydrochloric acid; insoluble in nitric acid;
safety instructions
GHS labeling of hazardous substances Caution
H and P phrases	H: 315-319-335
	P: 261-305 + 351 + 338
	As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Niobium (II) oxide is a chemical compound of niobium and oxygen . Along with niobium (V) oxide and niobium (IV) oxide, the gray solid is one of several stable oxides of niobium. In contrast to the other niobium oxides, the connection is electrically conductive (approx. 10 ⁶ S / cm) and is used as the anode material in niobium electrolytic capacitors .

Extraction and presentation

Niobium (II) oxide can be produced by reacting niobium oxides with elemental niobium at high temperatures. The exact ratio of the starting materials depends on the oxide used.

{\ displaystyle \ mathrm {Nb_ {2} O_ {5} +3 \ Nb \ longrightarrow 5 \ NbO}}

{\ displaystyle \ mathrm {NbO_ {2} + Nb \ longrightarrow 2 \ NbO}}

properties

Niobium (II) oxide has an unusual crystal structure . This can be described as an ordered defect structure that can be derived from the sodium chloride structure. Six niobium atoms form an octahedral cluster in which the central anion otherwise present in the sodium chloride structure is missing. At the same time, the niobium atoms are missing at the corners of the unit cell . The coordination environment, both for Nb around O and for O around Nb, is square planar.

Within the metal cluster there are niobium-niobium bonds with a bond length of 298 pm. These are very similar in length to those of elementary niobium (Nb-Nb: 285 pm) and determine the metallic properties of niobium (II) oxide.

use

Niobium (II) oxide is used as the anode material in niobium electrolytic capacitors. Like the corresponding tantalum capacitors, these play an important role in microelectronics , for example in laptops . Compared to tantalum capacitors, they are cheaper, but they cannot withstand such high voltages. Another advantage of niobium (II) oxide is its higher temperature stability compared to tantalum .

Further applications are coating for grounding electrodes of high-voltage direct current transmissions of (HVDC) as HVDC Italy-Greece to protect the earth electrode (anode) against corrosion in seawater.

Individual evidence

↑ ^a ^b ^c ^d data sheet Niobium (II) oxide, -100 mesh, 99.9% from Sigma-Aldrich , accessed on December 7, 2019 ( PDF ).
↑ ^a ^b Georg Brauer (Ed.) U. a .: Handbook of Preparative Inorganic Chemistry. 3rd, revised edition. Volume III, Ferdinand Enke, Stuttgart 1981, ISBN 3-432-87823-0 , p. 1462.
↑ ^a ^b Roger Blachnik (Ed.): Pocket book for chemists and physicists . Volume III: Elements, Inorganic Compounds and Materials, Minerals . founded by Jean d'Ans, Ellen Lax. 4th, revised and revised edition. Springer, Berlin 1998, ISBN 3-540-60035-3 , pp. 632 ( limited preview in Google Book search).
^ ^A ^b ^c Norman N. Greenwood, Alan Earnshaw: Chemistry of the Elements , 1st Edition, Wiley-VCH, Weinheim 1988, ISBN 3-527-26169-9 , pp. 1265-1266.
↑ ^a ^b Patent US7157073 : Production of high-purity niobium monoxide and capacitor production therefrom. Published on 2007 , inventor Charles A. Motchenbacher et al ..
^ Ch. Schnitter: The taming of niobium . In: Bayer research , Bayer AG, 2004 ( pdf ( memento of February 11, 2007 in the Internet Archive )).
↑ The Italy-Greece HVDC Link , Cigré , 2002, engl.

[Sigma-1] ta sheet Niobium (II) oxide, -100 mesh, 99.9% from Sigma-Aldrich , accessed on December 7, 2019 ( PDF ).

[brauer-2] Georg Brauer (Ed.) U. a .: Handbook of Preparative Inorganic Chemistry. 3rd, revised edition. Volume III, Ferdinand Enke, Stuttgart 1981, ISBN 3-432-87823-0 , p. 1462.

[Lax-3] Roger Blachnik (Ed.): Pocket book for chemists and physicists . Volume III: Elements, Inorganic Compounds and Materials, Minerals . founded by Jean d'Ans, Ellen Lax. 4th, revised and revised edition. Springer, Berlin 1998, ISBN 3-540-60035-3 , pp. 632 ( limited preview in Google Book search).

[Greenwood-4] A ^b ^c Norman N. Greenwood, Alan Earnshaw: Chemistry of the Elements , 1st Edition, Wiley-VCH, Weinheim 1988, ISBN 3-527-26169-9 , pp. 1265-1266.

[Motchenbacher-5] Patent US7157073 : Production of high-purity niobium monoxide and capacitor production therefrom. Published on 2007 , inventor Charles A. Motchenbacher et al ..

[6] Ch. Schnitter: The taming of niobium . In: Bayer research , Bayer AG, 2004 ( pdf ( memento of February 11, 2007 in the Internet Archive )).

[cigre1-7] The Italy-Greece HVDC Link , Cigré , 2002, engl.