In other Greek. mythology * a. niobium; n. Niob, Niobium; f. niobium; and. niobio), is a chemical element of group V of the periodic system of Mendeleev, atomic number 41, atomic mass 92.9064. Has one natural isotope 93 Nb.

Niobium oxide was first isolated by the English chemist C. Hatchet in 1801 from columbite. Metallic niobium was obtained in 1866 by the Swedish scientist K. V. Blomstrand.

Niobium properties

Niobium is a steel-colored metal, has a body-centered cubic lattice with a = 0.3294 nm; density 8570 kg/m 3 ; melting point 2500°C, boiling point 4927°C; heat capacity (298 K) 24.6 J / (mol.K); thermal conductivity (273 K) 51.4 W/(m.K); temperature coefficient of linear expansion (63-1103 K) 7.9.10 -6 K -1; specific electrical resistance (293 K) 16.10 -8 Ohm.m; thermal coefficient of electrical resistance (273 K) 3.95.10 -3 K -1. The transition temperature to the superconducting state is 9.46 K.

The oxidation state is +5, less often from +1 to +4. In terms of chemical properties, it is close to tantalum, extremely resistant to cold and, with slight heating, to the action of many aggressive media, incl. and acids. Niobium dissolves only hydrofluoric acid, its mixture with nitric acid and alkalis. Amphoterene. When interacting with halogens, it forms niobium halides. When Nb 2 O 5 is fused with soda, niobic acid salts are obtained - niobates, although the acids themselves do not exist in a free state. Niobium can form double salts and complex compounds. Non-toxic.

Getting and using

To obtain niobium, the niobium concentrate is fused with caustic soda or soda, and the resulting alloy is leached. The Nb and Ta contained in the undissolved precipitate are separated, and the niobium oxide is reduced separately from the tantalum oxide. Compact niobium is obtained by powder metallurgy, electric arc, vacuum and electron beam melting.

Niobium is one of the main components in the alloying of heat-resistant steels and alloys. Niobium and its alloys are used as structural materials for parts of jet engines, rockets, gas turbines, chemical equipment, electronic devices, electrical capacitors, and superconducting devices. Niobates are widely used as ferroelectrics, piezoelectrics, and laser materials.

Niobium

NIOBIUM-I; m.[lat. Niobium] Chemical element (Nb), a hard, refractory and malleable grayish-white metal (used in the production of chemically resistant and heat-resistant steels).

◁ Niobium; niobium, -th, -th.

(lat. Niobium), a chemical element of group V of the periodic system. Named after Niobe - the daughter of the mythological Tantalum (the proximity of the properties of Nb and Ta). Light gray refractory metal, density 8.57 g / cm 3, t mp 2477°C, superconducting transition temperature 9.28 K. Very chemically resistant. Minerals: pyrochlore, columbite, loparite, etc. A component of chemically resistant and heat-resistant steels, from which parts of rockets, jet engines, chemical and oil refinery equipment are made. Niobium and its alloys are coated with fuel elements (TVELs) of nuclear reactors. Stannide Nb 3 Sn, germanide Nb 3 Ge, alloys of niobium with Sn, Ti and Zr are used for the manufacture of superconducting solenoids (Nb 3 Ge is a superconductor with a superconducting transition temperature of 23.2 K).

NIOBIUM (lat. Niobium, on behalf of Niobe (cm. NIOBE)), Nb (read "niobium"), a chemical element with atomic number 41, atomic mass 92.9064. Natural niobium consists of one stable isotope 93 Nb. Configuration of two outer electron layers 4 s 2 p 6 d 4 5s 1 . Oxidation states +5, +4, +3, +2 and +1 (valencies V IV, III, II and I). It is located in group VB, in the 5th period of the Periodic Table of the Elements.
The radius of the atom is 0.145 nm, the radius of the Nb 5+ ion is from 0.062 nm (coordination number 4) to 0.088 nm (8), the Nb 4+ ion is from 0.082 to 0.092 nm, the Nb 3+ ion is 0.086 nm, the Nb 2+ ion is 0.085 nm. Sequential ionization energies are 6.88, 14.32, 25.05, 38.3 and 50.6 eV. The electron work function is 4.01 eV. Electronegativity according to Pauling (cm. PAULING Linus) 1,6.
Discovery history
Discovered in 1801 by C. Hatchet (cm. HATCHET Charles). Investigating a black mineral sent from America, he isolated the oxide of a new element, which he called columbium, and the mineral containing it, columbite. A year later, from the same mineral, A. G. Ekeberg (cm. EKEBERG Anders Gustav) isolated another oxide, which he called tantalum (cm. tantalum (chemical element)). The properties of columbium and Ta were very close, and they were considered as one element for a very long time. In 1844 G. Rose (cm. ROSE (German scientists, brothers)) proved that these are two different elements. He retained the name tantalum while the other named niobium. Only in 1950 IUPAC (World Organization of Chemists) finally assigned the name niobium to element No. 41. Metallic Nb was first obtained in 1866 by K. Blomstrand (cm. BLOMSTRAND Christian Wilhelm).
Being in nature
The content in the earth's crust is 2·10 -3% by weight. Niobium does not occur in free form; it accompanies tantalum in nature. Of the ores, columbite-tantalite is the most important. (cm. COLUMBITE)(Fe,Mn)(Nb,Ta) 2 O 6 , pyrochlore (cm. PYROCHLOR) and loparite (cm. LOPARIT).
Receipt
About 95% of Nb is obtained from pyrochlore, columbite-tantalite and loparite ores. Ores are enriched by gravity methods and flotation (cm. FLOTATION). Concentrates containing up to 60% Nb 2 O 5 are processed to ferroniobium (an alloy of iron and niobium), pure Nb 2 O 5 or NbCl 5 . Niobium is reduced from its oxide, fluoride or chloride by aluminum or carbothermia. High-purity niobium is obtained by high-temperature reduction of volatile NbCl 5 with hydrogen.
The resulting niobium powder is briquetted, sintered in vacuum in electric arc or electron beam furnaces.
Physical and chemical properties
Niobium is a shiny silver-gray metal with a cubic body-centered crystal lattice of the a-Fe type, a= 0.3294 nm. Melting point 2477°C, boiling point 4760°C, density 8.57 kg/dm 3 .
Chemically, niobium is quite stable. When calcined in air, it oxidizes to Nb 2 O 5 . About 10 crystalline modifications have been described for this oxide. At normal pressure, the b-form of Nb 2 O 5 is stable. When Nb 2 O 5 is fused with various oxides, niobates are obtained: Ti 2 Nb 10 O 29, FeNb 49 O 124. Niobates can be considered as salts of hypothetical niobic acids. They are divided into metaniobates MNbO 3, orthoniobates M 3 NbO 4, pyroniobates M 4 Nb 2 O 7 or polyniobates M 2 O . n Nb 2 O 5 (M is a singly charged cation, and n= 2-12). Niobates of two- and three-charged cations are known. Niobates react with HF, melts of alkali metal hydrofluorides (KHF 2) and ammonium (cm. AMMONIUM (in chemistry)). Some niobates with a high M 2 O/Nb 2 O 5 ratio are hydrolyzed:
6Na 3 NbO 4 + 5H 2 O \u003d Na 8 Nb 6 O 19 + 10NaOH
Niobium forms NbO 2 , NbO and a number of oxides intermediate between NbO 2.42 and NbO 2.50 and similar in structure to the b-form Nb 2 O 5 .
With halogens (cm. HALOGENS) Nb forms NbHal 5 pentahalides, NbHal 4 tetrahalides, and NbHal 2,67 -NbHal 3+x phases containing Nb 3 or Nb 2 groups. Niobium pentahalides are easily hydrolyzed by water. The melting points of pentachloride, pentabromide and niobium pentiodide are 205, 267.5 and 310°C. Above 200-250°C these pentahalides are volatile.
In the presence of water vapor and oxygen, NbCl 5 and NbBr 5 form oxyhalides NbOCl 3 (NbOBr 3) - loose cotton-like substances.
When Nb and graphite interact, Nb 2 C and NbC carbides, solid heat-resistant compounds, are formed. In the Nb - N system, there are several phases of variable composition and nitrides Nb 2 N and NbN. Nb behaves similarly in systems with phosphorus and arsenic. In the interaction of Nb with sulfur, sulfides were obtained: NbS, NbS 2 and NbS 3. Double fluorides Nb and K (Na) - K 2 have been synthesized.
Application
50% of the produced niobium is used for microalloying of steels, 20-30% - for the production of stainless and heat-resistant alloys. Niobium intermetallides (Nb 3 Sn and Nb 3 Ge) are used in the manufacture of solenoids for superconducting devices. Niobium nitride NbN is used in the manufacture of targets for television transmission tubes. Niobium oxides are components of refractory materials, cermets, glasses with high refractive indices. Double fluorides - in the isolation of niobium from natural raw materials, in the production of metallic niobium. Niobates are used in acoustic and optoelectronics as laser materials.
Physiological action
Niobium compounds are poisonous. MPC of niobium in water is 0.01 mg/l.

encyclopedic Dictionary. 2009 .

See what "niobium" is in other dictionaries:

- (new lat. niobium). One of the rare metals found in tantalite. Dictionary of foreign words included in the Russian language. Chudinov A.N., 1910. NIOBIUM metal, occurs in the form of oxides in rare minerals, has no practical significance ... Dictionary of foreign words of the Russian language

- (Niobium), Nb, chemical element of group V of the periodic system, atomic number 41, atomic mass 92.9064; metal, mp 2477 shC. Niobium is used for alloying steels, obtaining heat-resistant, hard and other alloys. Niobium was discovered by English ... ... Modern Encyclopedia

Niobium- (Niobium), Nb, chemical element of group V of the periodic system, atomic number 41, atomic mass 92.9064; metal, mp 2477 °C. Niobium is used for alloying steels, obtaining heat-resistant, hard and other alloys. Niobium was discovered by English ... ... Illustrated Encyclopedic Dictionary

- (symbol Nb), brilliant gray-white transition chemical element, metal. Discovered in 1801. It is found, as a rule, in pyrochlore ores. Being a soft and malleable metal, niobium is used in the production of special stainless steels and alloys ... ... Scientific and technical encyclopedic dictionary

Nb (lat. Niobium; from the name of Niobe, the daughter of Tantalus in other Greek mythology * a. niobium; n. Niob, Niobium; f. niobium; and. niobio), chem. element of group V periodic. Mendeleev systems, at. n. 41, at. m. 92.9064. It has one natural isotope 93Nb. ... ... Geological Encyclopedia

NIOBIUM, one of the metals discovered by chemists. Dahl's Explanatory Dictionary. IN AND. Dal. 1863 1866 ... Dahl's Explanatory Dictionary

NIOBIUM- chem. element, symbol Nb (lat. Niobium), at. n. 41, at. m. 92.90; light gray metal, density 8570 kg/m3, t = 2500 °C; has a high chem. tenacity. In nature, it occurs in minerals together with tantalum, separation from which causes ... ... Great Polytechnic Encyclopedia

- (lat. Niobium) Nb, a chemical element of group V of the periodic system, atomic number 41, atomic mass 92.9064. Named on behalf of Niobe, the daughter of the mythological Tantalus (the proximity of the properties of Nb and Ta). Light gray refractory metal, density 8.57 ... ... Big Encyclopedic Dictionary

- (Niobium), Nb, chem... Physical Encyclopedia

Exist., number of synonyms: 2 metal (86) element (159) ASIS synonym dictionary. V.N. Trishin. 2013 ... Synonym dictionary

- (Niobium French and English, Niob German; chemical), Nb =: 94. in group V of the periodic system of elements there are two rare metals, H. and tantalum, which are related to vanadium in the same way that molybdenum and tungsten are related to chromium; last three metal members… … Encyclopedia of Brockhaus and Efron

Physical properties of niobium

Niobium is a shiny, silvery-gray metal.

Elemental niobium is an extremely refractory (2468°C) and high-boiling (4927°C) metal, very resistant in many aggressive environments. All acids, with the exception of hydrofluoric, do not act on it. Oxidizing acids "passivate" niobium, covering it with a protective oxide film (No. 205). But at high temperatures, the chemical activity of niobium increases. If at 150...200°C only a small surface layer of the metal is oxidized, then at 900...1200°C the thickness of the oxide film increases significantly.

The crystal lattice of Niobium is body-centered cubic with the parameter a = 3.294A.

Pure metal is ductile and can be rolled into a thin sheet (up to a thickness of 0.01 mm) in a cold state without intermediate annealing.

It is possible to note such properties of niobium as a high melting and boiling point, a lower work function of electrons in comparison with other refractory metals - tungsten and molybdenum. The latter property characterizes the ability to electron emission (emission of electrons), which is used for the use of niobium in electrovacuum technology. Niobium also has a high superconducting transition temperature.

Density 8.57 g/cm3 (20 °C); mp 2500 °C; tbp 4927 °С; vapor pressure (in mm Hg; 1 mm Hg = 133.3 N/m2) 1 10-5 (2194 °C), 1 10-4 (2355 °C), 6 10- 4 (at tmelt), 1 10-3 (2539°C).

At ordinary temperatures, niobium is stable in air. The onset of oxidation (tint film) is observed when the metal is heated to 200-300°C. Above 500°, rapid oxidation occurs with the formation of Nb2O5 oxide.

Thermal conductivity in W / (m K) at 0 ° C and 600 ° C, respectively, 51.4 and 56.2, the same in cal / (cm s ° C) 0.125 and 0.156. The specific volume electrical resistance at 0°C is 15.22 10-8 ohm m (15.22 10-6 ohm cm). The transition temperature to the superconducting state is 9.25 K. Niobium is paramagnetic. The electron work function is 4.01 eV.

Pure niobium is easily processed by cold pressure and retains satisfactory mechanical properties at high temperatures. Its ultimate strength at 20 and 800 °C is 342 and 312 MN/m2 respectively, the same in kgf/mm234.2 and 31.2; relative elongation at 20 and 800°C, respectively, 19.2 and 20.7%. Hardness of pure Niobium according to Brinell 450, technical 750-1800 MN/m2. Impurities of some elements, especially hydrogen, nitrogen, carbon and oxygen, greatly impair plasticity and increase the hardness of Niobium.

Chemical properties of niobium

Niobium is especially valued for its resistance to the action of inorganic and organic substances.

There is a difference in the chemical behavior of powdered and lumpy metal. The latter is more stable. Metals do not act on it, even if they are heated to high temperatures. Liquid alkali metals and their alloys, bismuth, lead, mercury, tin can be in contact with niobium for a long time without changing its properties. Even such strong oxidizing agents as perchloric acid, "royal vodka", not to mention nitric, sulfuric, hydrochloric and all the others cannot do anything with it. Alkali solutions also have no effect on niobium.

There are, however, three reagents that can convert niobium metal into chemical compounds. One of them is a melt of the hydroxide of an alkali metal:

4Nb + 4NaOH + 5O2 \u003d 4NaNbO3 + 2H2O

The other two are hydrofluoric acid (HF) or its mixture with nitric acid (HF+HNO). In this case, fluoride complexes are formed, the composition of which largely depends on the reaction conditions. In any case, the element is part of an anion of the 2- or 2- type.

If we take powdered niobium, then it is somewhat more active. For example, in molten sodium nitrate, it even ignites, turning into an oxide. Compact niobium begins to oxidize when heated above 200°C, and the powder is covered with an oxide film already at 150°C. In this case, one of the wonderful properties of this metal is manifested - it retains plasticity.

In the form of sawdust, when heated above 900°C, it burns completely to Nb2O5. Burns vigorously in a stream of chlorine:

2Nb + 5Cl2 = 2NbCl5

When heated, it reacts with sulfur. With most metals, it alloys with difficulty. There are perhaps only two exceptions: iron, with which solid solutions of different ratios are formed, and aluminum, which has an Al2Nb compound with niobium.

What qualities of niobium help it resist the action of the strongest acids - oxidizing agents? It turns out that this does not refer to the properties of the metal, but to the features of its oxides. When in contact with oxidizing agents, a very thin (and therefore invisible) but very dense layer of oxides appears on the metal surface. This layer becomes an insurmountable barrier on the way of the oxidizing agent to a clean metal surface. Only some chemical reagents, in particular the fluorine anion, can penetrate through it. Therefore, essentially the metal is oxidized, but practically the results of the oxidation are imperceptible due to the presence of a thin protective film. Passivity in relation to dilute sulfuric acid is used to create an alternating current rectifier. It is arranged simply: platinum and niobium plates are immersed in a 0.05 m solution of sulfuric acid. Niobium in the passivated state can conduct current if it is a negative electrode - a cathode, i.e. electrons can pass through the oxide layer only from the side of the metal. From the solution, the path for electrons is closed. Therefore, when an alternating current is passed through such a device, only one phase passes, for which platinum is the anode, and niobium is the cathode.

niobium metal halogen

There are a fairly large number of elements that, when combined with other substances, form alloys with special performance properties. An example is niobium - an element that was first called "columbium" (after the name of the river where it was first found), but was later renamed. Niobium is a metal with rather unusual properties, which we will discuss in more detail later.

Getting an element

When considering the properties of niobium, it should be noted that the content of this metal per ton of rock is relatively small, approximately 18 grams. That is why, after its discovery, quite a few attempts were made to obtain the metal artificially. Due to the similar chemical composition, this substance is often mined together with tantalum.

Deposits of niobium are located almost all over the world. An example is the mines in the Congo, Rwanda, Brazil and many other countries. However, this element cannot be called widespread; in many regions it is practically not found even in low concentrations.

The relatively low concentration of a substance in the earth's rock is aggravated by the difficulties that arise when it is obtained from a concentrate. It should be borne in mind that NBSh niobium can only be obtained from rocks that are saturated with tantalum. The features of the production process are the following points:

1. To begin with, concentrated ore is supplied to the plant, which goes through several stages of purification. In the production of niobium, the resulting ore is separated into pure elements, including tantalum.
2. The final processing process is metal refining.

Despite the difficulties encountered in the extraction and processing of the ore in question, every year the volume of production of the alloy in question increases significantly. This is due to the fact that the metal has exceptional performance and is widely used in various industries.

Niobium oxides

The considered chemical element can become the basis of various compounds. The most common is niobium pentoxide. Among the features of this connection, the following points can be noted:

1. Niobium oxide is a white crystalline powder that has a creamy tint.
2. The substance is insoluble in water.
3. The resulting substance retains its structure when mixed with most acids.

The following properties can also be attributed to the features of niobium pentoxide:

1. Increased strength.
2. High toughness. The substance is able to withstand temperatures up to 1490 degrees Celsius.
3. When heated, the surface oxidizes.
4. Responds to chlorine, can be reduced by hydrogen.

Niobium hydroxide is in most cases used to obtain high-alloy steel grades, which have quite attractive performance characteristics.

Physical and chemical properties

Niobium has chemical properties similar to those of tantalum. Considering the main characteristics of niobium, you need to pay attention to the following points:

1. Resistant to various types of corrosion. The alloys obtained by introducing this element into the composition have high corrosion-resistant qualities.
2. The considered chemical element demonstrates a high melting point. As practice shows, most alloys have a melting point of more than 1,400 degrees Celsius. this complicates the processing process, but makes metals indispensable in various fields of activity.
3. The main physical properties are also characterized by the ease of welding of the obtained alloys.
4. At negative temperatures, the structure of the element remains practically unchanged, which makes it possible to preserve the operational properties of the metal.
5. The special structure of the niobium atom determines the superconducting qualities of the material.
6. The atomic mass is 92.9, the valency depends on the characteristics of the composition.

The main advantage of the substance is considered to be refractoriness. That is why it has been used in various industries. The melting of the substance takes place at a temperature of about 2,500 degrees Celsius. Some alloys even melt at a record temperature of 4,500 degrees Celsius. The density of the substance is quite high, it is 8.57 grams per cubic centimeter. It should be borne in mind that the metal is characterized by paramagnetism.

The following acids do not affect the crystal lattice:

1. sulfuric;
2. salt;
3. phosphoric;
4. chloride.

Does not affect metal and aqueous solutions of chlorine. With a certain impact on the metal, a dielectric oxide film is formed on its surface. That is why the metal began to be used in the production of miniature high-capacity capacitors, which are also made from more expensive tantalum.

Application of niobium

A wide variety of niobium products are manufactured, most of which are associated with the production of aviation equipment. An example is the use of niobium in the manufacture of parts that are installed when assembling rockets or aircraft. In addition, the following use of this element can be distinguished:

1. Production of elements from which radar installations are made.
2. As previously noted, the alloy in question can be used to obtain cheaper capacitive electrical capacitors.
3. Foil cathodes and anodes are also made using the element in question, which is associated with high heat resistance.
4. You can often find designs of powerful generator lamps that have a grid inside. In order for this grid to withstand high temperatures, it is made from the alloy in question.

High physical and chemical qualities determine the use of niobium in the production of pipes for transporting liquid metals. In addition, alloys are used to produce containers for various purposes.

Alloys with niobium

Considering such alloys, it should be taken into account that this element is often used for the production of ferroniobium. This material has been widely used in foundry industries, as well as in the manufacture of electronic coatings. The composition includes:

1. iron;
2. niobium with tantalum;
3. silicon;
4. aluminum;
5. carbon;
6. sulfur;
7. phosphorus;
8. titanium.

The concentration of the main elements can vary over a fairly wide range, on which the performance of the material depends.

Niobium 5VMTs can be called an alternative ferroniobium alloy. When it is obtained, tungsten, zirconium and molybdenum are used as alloying elements. In most cases, this spawn is used for the production of semi-finished products.

In conclusion, we note that niobium is used in some countries in the production of coins. This is due to the rather high cost of the material. With the mass production of alloys that have niobium as the main element, original ingots are created.

MetProd has been working in the mining and production of raw materials and metals for more than 20 years, and during this time we have achieved the highest quality of our products. We are engaged in the extraction of rare refractory metals, which include the element niobium - a metal, the properties and scope of which allow it to be used in the most critical industries. We can guarantee the quality of products, because we develop niobium deposits on our own.

Niobium and its features

This metal is very resistant to various kinds of chemical influences - this determines its popularity in industry and high cost. Among the areas of its application, the most responsible are medicine, the diamond and rocket industry, and the production of coins. In addition, the material is quite malleable during processing, if it is carried out at low temperatures. Niobium has a high transition temperature - this property is very important in the production of superconducting wires and magnets.

It is supplied in ingots, powder or ligature. Thus, the most famous powder of the N6PM brand contains, in addition to niobium, carbon, nitrogen, oxygen, iron, titanium, tantalum and silicon and can have one of four grain sizes (40–100 μm).

The chemical stability of niobium is manifested when interacting with substances such as nitric, orthophosphoric, sulfuric and hydrochloric acids. It can only be dissolved in a very high concentration of caustic alkali or sulfuric acid, also concentrated and preheated to 150 ° C.

What is niobium used for?

Metals with unique properties are very much needed by various branches of metallurgy, because it significantly optimizes the characteristics of steels. From alloys with the participation of niobium, such critical products are produced as:

• pipes and containers for gas pipelines, oil pipelines, for molten metals;
• shells of atomic and nuclear reactors;
• parts of electrolytic capacitors;
• various refractory materials, special glasses and fittings for lamps;
• carbides;
• fixtures for the chemical industry requiring high corrosion resistance;
• "hot" fittings for generator and electronic tubes for radars - cathodes, anodes, grids, etc.

Currently, the demand for niobium is increasing, and the company is trying to satisfy all market demands: in order to be able to buy niobium at a low price, we ourselves control its extraction and production at all stages. We offer pure metal, as well as its alloys, which are used in rocketry, for the production of parts for aviation and space technology, in electronics and radio engineering, nuclear power engineering and in chemical apparatus building.

Approximately half of all niobium currently on the market is used for alloying steels, and about 30% is used to obtain alloys with the desired properties. They are alloyed with non-ferrous metals, including uranium, introduced into steel to avoid intergranular corrosion and improve its properties.