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Niobium pentoxide is the inorganic compound with the formula Nb 2 O 5. A colorless, insoluble, and fairly unreactive solid, it is the most widespread precursor for other compounds and materials containing niobium. It is predominantly used in alloying, with other specialized applications in capacitors, optical glasses, and the production of ...
Niobium forms oxides in the oxidation states +5 (Nb 2 O 5), [77] +4 (NbO 2), and the rarer oxidation state, +2 . [78] Most common is the pentoxide, precursor to almost all niobium compounds and alloys. [61] [79] Niobates are generated by dissolving the pentoxide in basic hydroxide solutions or by melting it in alkali metal oxides.
Niobium oxide, archaically called columbium oxide, [1] may refer to: Niobium monoxide (niobium(II) oxide), NbO; Niobium dioxide (niobium(IV) oxide), NbO 2; Niobium pentoxide (niobium(V) oxide), Nb 2 O 5; In addition to the above, other distinct oxides exist general formula Nb 3n+1 O 8n−2 where n ranges from 5 - 8 inclusive, e.g. Nb 8 O 19 (Nb ...
Ferroniobium is an important iron-niobium alloy, with a niobium content of 60-70%. [1] It is the main source for niobium alloying of HSLA steel and covers more than 80% of the worldwide niobium production. The niobium is mined from pyrochlore deposits and is subsequently transformed into the niobium pentoxide Nb 2 O 5.
The aluminothermic reaction is used for the production of several ferroalloys, for example ferroniobium from niobium pentoxide and ferrovanadium from iron, vanadium(V) oxide, and aluminium. [1] [2] The process begins with the reduction of the oxide by the aluminium: 3 V 2 O 5 + 10 Al → 5 Al 2 O 3 + 6 V
Vanadium(V) oxide or vanadium pentoxide is the most common, being precursor to most alloys and compounds of vanadium, and is also a widely used industrial catalyst. [29] Niobium forms oxides in the oxidation states +5 (Nb 2 O 5), [30] +4 (NbO 2), and the rarer oxidation state, +2 . [31]
Niobium(V) can form complexes with hydroxy acids, as well as oxalic acid. The salt formed is more complex than tartaric acid for niobium (as opposed to tantalum). [3] NH 4 [NbO(C 2 O 4) 2 (H 2 O) 2]·3H 2 O starts to lose water at 125°C, and at 630°C, it fully decomposes, forming a compound known as niobium pentoxide; [4] Heating this complex and sodium citrate at 650°C can form sodium ...
N.B. Pilling and R.E. Bedworth [2] suggested in 1923 that metals can be classed into two categories: those that form protective oxides, and those that cannot. They ascribed the protectiveness of the oxide to the volume the oxide takes in comparison to the volume of the metal used to produce this oxide in a corrosion process in dry air.