The isolation of neodymium from its mineral occurred at the end of the 19th century. This was done by a chemist of German origin, Karl Auer von Welsbach. For a long time, the scientific community did not attach due importance to this discovery. Neodymium was considered a useless, unpromising metal. The only place where it has been used is in the manufacture of silicon for lighters.
But everything changed when humanity discovered ways to obtain energy through the fission of atomic nuclei. The nuclear industry needed new materials, one of which was neodymium. What properties allowed it to become widespread in highly scientific production?
Physical properties
Neodymium is a typical representative of rare earth metals. It has a silvery-white color. Belongs to the lanthanide group. Under natural conditions it occurs in the form of 7 isotopes, two of which are radioactive. Their half-life is 14 days.
The density of metallic neodymium is less than that of structural steels and is equal to 7007 kg/m3. Melting point 1024 ºС. The temperature at which the metal begins to boil is 3050 ºС. Neodymium has a high thermal conductivity. The thermal conductivity coefficient is 13.5 W/m K.
The temperature coefficient of linear expansion is 6.7*10-6 1/C, i.e. with an increase in temperature of 1 degree, the metal will expand by 6.7 microns. Specific resistance to electric current is 0.64 μOhm*m. Paramagnetic Magnetic field susceptibility is 39.5*10-9 units.
Chemical properties
Neodymium is an element with increased activity. Forms alloys with most currently known metals.
Neodymium metal has strong reducing properties. The metal actively interacts with hydrochloric, sulfuric, nitric and other acids. Inert towards hydrofluoric and orthophosphoric acids. The reason for this lies in the presence of a protective film on the surface of neodymium, consisting of soluble salt compounds.
In air saturated with moisture, neodymium is covered with a thin hydroxide film. At temperatures above 300 ºС, the combustion process begins. When heated above 500 ºС, neodymium enters into chemical reactions with elements such as hydrogen, phosphorus, carbon, sulfur, and nitrogen.
Mechanical properties
A distinctive feature of neodymium is its high ductility. Young's modulus (of elasticity) is 37 GPa. Shear modulus 13.5 GPa. The relative compressive elongation is 40%, which is comparable to that of copper.
Neodymium does not have high strength characteristics. The tensile strength is 136 MPa, which is almost 4 times lower than that of steel 45. The hardness of neodymium metal depends on the amount of impurities in its composition. Elements such as phosphorus increase its value, but at the same time negatively affect strength. For pure neodymium, the hardness is 314 units on the Brinell scale.
Technological properties
The increased plasticity of the metal provides it with the ability to use all types of hot and cold forming: stamping, forging, embossing, etc. Stamped neodymium blanks are highly accurate due to the low value of metal shrinkage.
Metal can be cut. Due to its increased viscosity, it is not possible to achieve high cutting speeds during processing. They fluctuate between 40-60 m/s.
Neodymium metal does not change its mechanical characteristics by heat treatment. Doesn't weld. Partially weldable.
Neodymium compounds
As mentioned earlier, neodymium actively enters into chemical bonds with other elements. The most commonly used in practice are:
- Neodymium oxide is a bluish-gray compound with a density of 7325 kg/m3. Refractory. Melting point 2300 C. Insoluble in alkali and water.
- Neodymium fluoride is a pale pink crystal with a melting point of 1375 C.
- Neodymium chloride is a violet-pink compound with a density of 4135 kg/m3. It has a relatively low melting point of 760 C. It is highly soluble in water.
Application
The widespread use of neodymium in production has two main reasons:
- Widely distributed in nature. The lithosphere contains an average of 2.5 grams per ton of land, and sea water 0.02 * 1 microgram per 1000 liters. Its percentage on the planet is higher than that of metals such as gold, nickel, aluminum, etc.
- Relatively low prices.
In production, the following methods of using this rare earth metal are distinguished:
- Glass industry. Along with other rare earth metals, neodymium is a component of glass that changes color depending on the intensity of light. It also serves as a component of “illuminating” glass used in the manufacture of optical equipment. Safety glasses are made from neodymium alloys to ensure the safety of the welding process. The reason for this was the ability of the metal to absorb ultraviolet radiation. Neodymium metal is used to produce infrared filters used in astronomers' optical equipment. The ability of neodymium glass to prevent the penetration of neutrons has found its use in the production of protection for thermonuclear reactors.
- In the metallurgical industry, neodymium is used as a steel deoxidizer. The introduction of neodymium into a nickel alloy increases its ductility by 30-40%, which makes it possible to process the metal under pressure. Magnesium alloys alloyed with neodymium retain their mechanical properties at higher temperatures. Titanium containing niobium has better strength and corrosion resistance compared to pure metal.
- In the nuclear industry, neodymium metal is used to produce plutonium from a uranium-plutonium solution. Plutonium is released much faster in the presence of neodymium particles, which makes it possible to carry out its uniform extraction from liquid uranium. In addition, neodymium increases the quality characteristics of uranium fuel.
- Most modern industrial magnets are based on an iron-boron-neodymium compound. Compared to samarium-cobalt magnets, they have higher magnetic force values.
- The chemical industry uses neodymium as a catalyst in the manufacture of various types of polymers.
- In addition, it serves as raw material for laser emitter crystals. Neodymium lasers are actively used in plastic surgery for figure correction.
- Used as a structural material in the rocket and space industry. Neodymium rolled metal is a blank for parts installed on orbital satellites and spacecraft.
- In electronics, neodymium is used in the production of cathode ray tubes, which are characterized by increased color contrasts.
Neodymium is a chemical element with the symbol Nd and atomic number 60. It is a soft, silvery metal that tarnishes when exposed to air. It was discovered in 1885 by the Austrian chemist Karl Auer von Welsbach. The substance is present in significant quantities in deposits of monazite sand and minerals such as bastnäsite.
Story
The rare earth metal neodymium was discovered by the Austrian chemist Baron Karl Auer von Welsbach in Vienna in 1885. The scientist isolated the new substance (as well as the element praseodymium) from a material known as didymium through the fractional crystallization of ammonium nitrate double tetrahydrate from nitric acid, after separation by spectroscopic analysis. However, until 1925 it was not possible to obtain the element in its pure form.
Until the late 1940s, the main commercial method was double crystallization of nitrates. The method is ineffective, and the amount of substance obtained was small. Lindsay Chemical Division was the first to begin large-scale production of neodymium using ion exchange purification. Since the 1950s, the highly purified (above 99%) element has primarily been produced through an ion exchange process from rare earth-rich monazite by electrolysis of its halide salts.
Currently, most neodymium metal is extracted from bastnäsite. Advancing technology and the development of improved cleaning methods have allowed it to be widely used in industry.
Description
The chemical element does not occur naturally in metallic form, but is isolated from the substance didymium, in which it is mixed with other lanthanides (particularly praseodymium). Although classified as a rare earth, neodymium is a fairly common element, occurring at least as often as cobalt, nickel or copper, and is widespread in the earth's crust. Most of the substance is mined in China.
Neodymium compounds were first used commercially as glass dyes in 1927, and they remain a popular additive in spectacle lenses. The color of neodymium compounds, due to the presence of Nd 3+ ions, often has a reddish-purple hue, but this varies depending on the type of lighting.
Application
Neodymium-doped lenses are used in lasers that emit infrared radiation with wavelengths between 1047 and 1062 nanometers. They are used in systems that have extremely high power, such as inertial containment experiments.
Neodymium metal is also used with other crystals (such as yttrium aluminum garnet) in the Nd:YAG series of lasers. This installation typically emits infrared rays with a wavelength of approximately 1064 nm. It is one of the most commonly used
Another important use of neodymium metal is as a reinforcing component in alloys used to make powerful, high-strength permanent magnets. They are widely used in products such as microphones, professional loudspeakers, in-ear headphones, high-performance DC motors, computer hard drives - wherever low magnetic mass (volume) or high magnetic fields are required.
Large neodymium magnets are used in high power and weight electric motors (such as hybrid cars) and generators (such as aircraft and wind farm electrical generators). The element is also used to strengthen some alloys. For example, titanium becomes one and a half times stronger after adding only 1.5% of this substance.
Physical properties
Neodymium metal is present in classical mischmetal (an alloy of rare earth elements), where its concentration is usually about 18%. In its pure form, the element has a bright silver-golden metallic luster, but quickly oxidizes in ordinary air. A layer of oxide forms and peels off, exposing the metal to further oxidation. Thus, a centimeter sample of the substance is completely oxidized within a year.
Neodymium typically exists in two allotropic forms with a center-to-center conversion from a double hexagonal cubic structure. It begins to melt at 1024°C and boil at 3074°C. The density of the substance in the solid phase is 7.01 g/cm3, in the liquid state - 6.89 g/cm3.
Atomic properties:
- Oxidation state: +4, +3, +2 (basic oxide).
- Electronegativity: 1.14 (Pauling scale).
- Thermal conductivity: 16.5 W/(m K).
- Ionization energy: 1: 533.1 kJ/mol, 2: 1040 kJ/mol, 3: 2130 kJ/mol.
- Atomic radius: 181 picometers.
Chemical properties
Neodymium metal dulls slowly in air and burns easily at about 150°C to form neodymium(III) oxide:
4Nd + 3O 2 → 2Nd 2 O 3
This is an electropositive element. It reacts slowly with cold water, but quite quickly with hot water, forming neodymium (III) hydroxide:
2Nd(s) + 6H 2 O(l) → 2Nd(OH) 3 (aq) + 3H 2 (g)
The metal reacts vigorously with all halogens and readily dissolves in dilute sulfuric acid to form solutions that contain the violet ion Nd(III).
Production
Neodymium metal is never found in nature as a free element. It is extracted from ores such as bastnaesite and monazite, in which it is associated with other lanthanides and other elements. The main mining areas for these minerals are in China, the USA, Brazil, India, Sri Lanka and Australia. Small deposits have also been explored in Russia.
Neodymium reserves are estimated at approximately 8 million tons. Its concentration in the Earth's crust is about 38 mg/kg, which is the second highest among rare earth elements after cerium. World metal production is about 7,000 tons. The bulk of production belongs to China. The Chinese government recently recognized the element as strategically important and introduced restrictions on its export, causing some concern in consumer countries and causing a sharp increase in neodymium prices to $500. Today, the average price per kilogram of pure metal varies between $300-350, neodymium oxides are cheaper: $70-130.
There are cases when the price of metal dropped to $40 due to illegal trade in circumvention of Chinese government restrictions. Uncertainty over pricing and availability has led Japanese companies to develop permanent magnets and associated electric motors with fewer or no rare earth elements.
); at. n. 60, at. m. 144.24. Nature the mixture consists of stable isotopes 142 Nd (27.07%), 143 Nd (12.17%), 145 Nd (8.30%), 146 Nd (17.22%), 148 Nd (5.78%) and radioactive isotopes 144 Nd (23.78%, T 1/2 5 . 10 15 g), l50 Nd (5.67%, T 1/2 2 . 10 15 g). External configuration electron shells of the atom 4s 2 4p 6 4d 10 4f 4 5s 2 5p 6 6s 2 ; oxidation state + 3, +4, less often + 2; ionization energy at sequential transition from Nd 0 to Nd 4+ resp. 5.49, 10.72, 22.14, 40.41 eV; radii: atomic 0.182 nm, ionic (coordination number in brackets) for Nd 3+ 0.112 nm (6), 0.125 nm (8), 0.130 nm (9), 0.141 nm (12), for Nd 2+ 0.143 nm ( 8), 0.149 nm (9).
N Eodym is one of the most common REEs. Content in the earth's crust is 2.5. 10 -3% by weight, in sea water 9.2. 10 -6 mg/l. Along with other rare earth elements of the cerium subgroup, the minerals contain monazite, bestnesite (up to 20% Nd 2 O 3), and loparite.
Properties. Neodymium metal is light gray in color; up to 885 °C there is an a-modification with hexagon. La-type lattice, a = 0.36579 nm, c = 1.17992 nm, z = 4, space. group P6 3 /tts; high temperature b-shape-cubic. type a-Fe, a = 0.413 nm, z = 2, space. Fm3m group; Transition DH a<=>b 3.0 kJ/mol; m.p. 1016 °C, bp. 3027 °C; dense a-Nd 6.908 g/cm 3 , b-Nd 6.80 g/cm 3 ; C 0 p 27.42 JDmol K); DH 0 pl 7.15 kJ/mol; S 0 n298 71.68 JDmol. TO); steam pressure 4.50. 10 -3 Pa (1016°C): temperature coefficient. linear expansion 6.7-10~ 6 K, p 6.43-10: 5 Ohm-cm; paramagnetic, magnetic susceptibility +5.628. 10 -3; below 20 K (Neel point) - antiferromagnet; Brinell hardness 350-450 MPa. Easily amenable to mechanical processing in an Ar atmosphere. Neodymium is more resistant to oxidation by air than La, Ce and Pr, but less resistant than heavy rare earth elements. When heated in air, it quickly oxidizes. It reacts violently with minerals, interacting . with boiling water. Reacts with halogens, N 2, H 2, especially when heated. Only Nd(III) compounds are stable in aqueous media. Known compounds Nd(IY)-Cs 3 and Ba 2 (Ce,Nd) 2 O 6. Dihalides NdX 2 were obtained.
Stable complex connections. with polydentate ligands it forms Nd(III) (coordination number 6-12). Complex formation with monodentate ligands is not typical for neodymium.
Sesquioxide Nd 2 O 3 - bluish-violet crystals with cubic. lattice (a = 1.1140 nm, z = 16, space.group Ia3); hexagon is known. modification And i (a = 0.3831 nm, c = 0.6008 nm, z = 1, space group C3m); m.p. 2320 °C; dense 7.327 g/cm3; C 0 p 111.3 JDmol. TO); DH 0 sample - 1808.3 kJ/mol; S 0 298 158.5 JDmol. TO); obtained by the decomposition of Nd(NO 3) 3, Nd 2 (C 2 O 4) 3 or other salts in air, usually at 800-1000 ° C. The temporary permissible concentration in the air of the working area is 6 mg/m3.
T r i f t o r i d NdF 3 -pale-ro h New crystals with trigons. grating (space group Р3С1, z = 6, for hexagonal installation a = 0.7030 nm, c = 0.7200 nm); m.p. 1377 °C, bp. 2300 °C; C 0 p 94.9 JDmol. TO); DH 0 sample - 1679.0 kJ/mol; S 0 298 121.3 JDmol. TO); receive interaction Nd 2 O 3 with HF gas at 700 °C, precipitation of Nd(III) salts from aqueous solutions by the action of HF, thermal. decomposition of fluoroammonium complexes at 400-500 °C in an atmosphere of Ar, N 2, etc.; used to obtain pure neodymium metallothermic. way as a component of laser fluoride materials.
Trichloride NdCl 3 - pink-violet hygroscopic crystals with a hexagon. lattice (a = 0.7381 nm, c = 0.4231 nm, z = 2, space group C6 3 /m); m.p. 758 °C, bp. 1690 °C; C 0 p 99.24 JDmol. TO); DH 0 arr - 1040.6 kJ/mol; S 0 298 153.0 JDmol. TO); with HBr and HI easily transforms into the corresponding trihalides; forms hydrates; receive interaction mixtures of Сl 2 and СCl 4 with Nd 2 O 3 or Nd 2 (C 2 O 4) 3 above 200 °С and other methods; anhydrous NdCl 3 is used to obtain metallothermic neodymium metal. way. LD 50 4 g/kg (mice, subcutaneous).
Receipt. During the separation of rare earth elements, neodymium is concentrated together with light lanthanides and released together with Pr; mixture of conc. Pr(III) and Nd(III) are called didymos. Neodymium metal is obtained from anhydrous halides by electrolysis of their melt or by calcium thermal
Introduction
general characteristics
History of discovery
Occurrence in nature and natural isotopes
Receipt
Physical properties
Chemical properties
Neodymium compounds
Application
Conclusion
Literature
Introduction
Among the 110 known chemical elements, there are 14 twin elements whose properties are as similar to each other as two peas in a pod. These are the so-called rare earth elements, or lanthanides. In D. I. Mendeleev’s periodic system of chemical elements, they are located in one cell. The reason for this arrangement of rare earth elements is the uniqueness of their electronic structure and, as a consequence, the extreme similarity of properties.
For a long time these elements were considered rare. Only studies of recent decades have shown that there are more of them in the earth’s crust, much more than such metals as lead, mercury, and gold, which have long been known to people. Lanthanides were considered unpromising for practice. Making flints for lighters was their main use.
The development of technology, mainly atomic technology, required new materials with a wide variety of properties. Scientists and engineers have turned their attention to rare earth elements. Now they are one of the most important materials for new technology. From space rockets to pharmaceuticals - this is the range of their applications.
Therefore, it is very important to study their individual properties and look for new areas of application.
general characteristics
Neodymium (from the Greek neos - new and didymos - twin, double) is a chemical element of group III of the 6th period of the periodic table of chemical elements of D.I. Mendeleev, it belongs to the rare earth elements - lanthanides.
Basic constants and properties of neodymium:
Atomic number 60 Atomic mass 144.24 Number of known isotopes 24 Number of natural isotopes 7 MoleculeNd Density, g/cm37.008 Melting point, oC1024 Boiling point, oC3027 Oxidation states 0. +3 Ionization potential, eV5.46 Electron affinity, eV-0.52 Relative electromotive negativity 1.07 Electrode potential, V-2.43 Configuration of external electronic atomic shells4f46s2Atomic radius, pm182Covalent radius, pm164Ionic radius (Nd3+), pm104Clark, %2.5*10-3
History of discovery
In the Middle Ages, alchemists identified a group of substances that were almost insoluble in water and acids (no gas bubbles were released from acid solutions), did not change when heated, did not melt, and were alkaline in nature. These substances were given a common name land .
In 1787, Swedish army lieutenant Karl Arrhenius discovered an unknown mineral in an abandoned quarry near the town of Ytterby, which was later named ytterbite after the town in which it was found. In 1794, Johan Gadolin analyzed ytterbite and showed that this mineral, in addition to oxides of beryllium, silicon and iron, contains 38% oxide of an unknown element. New land Axel Eksberg named it in 1797 yttrium , the corresponding element is yttrium. Around the same time, different groups of researchers studied another mineral - ochroite (Ln2o3 xSiO2 yH2O, where Ln is a lanthanide), and in 1803, almost simultaneously and independently of each other, Martin Klaproth and J. Berzelius with W. Hisinger isolated from it land which was named cerium , the element was cerium, and the mineral ochrite was renamed cerite. Discovery of the first lanthanide element - cerium and its relative - yttrium is the most turbulent part of the first stage of the history of rare earth elements. From these two lands a long chain of false and true discoveries of new elements began. In 1839, Karl Mossander, while studying cerium nitrate, discovered an admixture of an unknown element in it. After studying it, he came to the conclusion that it was a new Earth and he called her lanthanum , and the element is lanthanum. In 1841, K. Mossander isolated from the new land one more. She looked a lot like lanthanum earth , therefore the corresponding element was called didyme - from the Greek word didymos - double , or doubles .
In 1878, the French chemist M. Delyafontaine discovered the heterogeneity of didyme, and in 1879 L. Boisbaudran isolated a fraction from it, the corresponding element was called samarium, and didymite continued to be listed as an element. But in 1885, the Austrian chemist Karl Auer von Welsbach separated didymium into two elements. To do this, he used the method of fractional crystallization of double ammonium salts: one fraction included salts of green color (they corresponded to a pale green oxide), the other - salts of a violet to red color (they corresponded to a grayish-blue oxide). He called the element that produces green salts praseodymium, and the second element neodymium (i.e., new didymium). In the form of a metal, neodymium was obtained by a group of German scientists led by W. Muthmann in 1902. Occurrence in nature and natural isotopes Neodymium is the second most abundant of all lanthanides. There is even more of it in the earth's crust than lanthanum itself - 2.5 * 10-3 and 1.8 * 10-3% by weight, respectively; sea water contains 9.2 * 10-6 mg/l. Neodymium forms its own mineral - aeshinite, where it is more abundant than other lanthanides and their satellites - thorium, tantalum, niobium, and alkaline earth metals. Natural neodymium is a mixture of seven isotopes with mass numbers: 142 (27.11%), 143 (12.17%), 144 (23.85%), 145 (8.30%), 146 (17.22%) , 148 (5.73%), 150 (5.62%). For isotopes, the geochemical law is observed: in nature, the content of an isotope with an even mass number is higher than that of its neighbor with an odd one. Second most abundant isotope 144Nd α- radioactive with a half-life of 2.4*1015 years. Of the artificially obtained radioactive isotopes (there are about a dozen), only one, 147Nd, can serve as a radioactive tracer. It emits β-, γ- rays and has a half-life of 11.1 days. All other isotopes of neodymium are very short-lived. Receipt Rare earth element minerals are complex in composition and it is very difficult to isolate the elements they contain. But it is even more difficult to separate a mixture of rare earth elements. The oldest, classical separation methods: fractional, fractional crystallization and fractional basic precipitation. Currently, new methods are being developed: chromatography (ion exchange) and extraction with organic solvents. When separating rare earth elements, neodymium is concentrated together with light lanthanides (cerium subgroup) and isolated together with praseodymium, such a mixture of praseodymium and neodymium is called didymium. Neodymium is then purified from impurities by ion exchange (using ethylenediaminetetraacetic acid or using Cu resin) or by separation from chloride mixtures. Neodymium metal is obtained from anhydrous halides by electrolysis of their melt, in the presence of lithium, potassium, calcium, barium halides: NdCl3 (melt) → 2Nd + 3Cl2 And also by thermal reduction of neodymium (III) oxide with calcium: 2O3 + 3Ca → 2Nd + 3CaO. Physical properties Neodymium, like all lanthanides, is a transition f element, since as the nuclear charge increases from 57 to 71, the 4f sublevel is filled. Therefore, lanthanides have properties that are extremely close to each other. Neodymium is a silvery-white typical metal. Its color is due to the presence of an oxide film on its surface. Neodymium is a ductile, refractory, malleable metal, but has a relatively low hardness and is easy to machine. It has paramagnetic properties, which are explained by the presence of an unfinished 4f sublevel, which has high magnetic activity. Chemical properties Neodymium is an active metal; its reaction behavior is similar to lanthanum. In humid air it becomes covered with an oxide-hydroxide film. Nd + 6H2O + 3O2 → 4Nd(OH)3. Neodymium is passivated in cold water, does not react with alkalis and ethanol, but reacts with water when heated: Nd + 6H2O (hor.) → 2Nd(OH)3↓ + 3H2 Neodymium is a strong reducing agent and reacts violently with acids: Nd + 6HCl (dil.) → 2NdCl3 + 3H2 Nd + 6 HNO3 (conc.) → Nd(NO3)3 + 3NO2 + 3H2O. Neodymium is stable in hydrofluoric and phosphoric acids, as it is covered with a protective film of insoluble salts. At 300°C it burns in air: Nd + 3O2 → 2Nd2O3. Interacts with halogens with chlorine (at 300°C): Nd + 3Cl2 → 2NdCl3 And when heated, it interacts with nitrogen, sulfur, carbon, silicon, phosphorus, hydrogen with sulfur (at 500-800oC): Nd + 3S → Nd2S3 with nitric oxide (IV): 6NO2 → 3NO + Nd(NO3)3 with hydrogen (at 300°C): Nd + 3H2 → 2NdH3. Forms alloys with most metals. Neodymium compounds Neodymium in compounds exhibits only one oxidation state +3; numerous binary compounds and various salts are known for it. The color of its compounds is not the same: Nd2O3 oxide is bluish-violet, nitrate and chloride are lilac, NdF3 fluoride is light pink, NdBr3 bromide is violet, NdI3 iodide is green, Nd2S3 sulfide is dark green, NdC carbide is brown, NdB6 hexaboride is blue, etc. Neodymium (III) oxide Nd2O3 The melting point of neodymium oxide is 2320°C, boiling point - 4300°C, density - 7.327 g/cm3. Neodymium oxide is obtained by decomposition of nitrate, oxalate and other neodymium salts in air at 800-1000°C: Nd(NO3)3 → Nd2O3 + 3N2O5 These are bluish-violet crystals, insoluble in water and alkalis. Neodymium oxide exhibits weakly basic properties and dissolves in acids: 2O3 + 6HCl → 2NdCl3 + 3H2O. When interacting with alkali metal oxides, it exhibits some amphoteric properties: O3 + Na2O → 2NaNdO2. Pale pink crystals, insoluble in water. The melting point of fluoride is 1377°C, the boiling point is 2300°C. Neodymium fluoride is obtained by reacting neodymium oxide with hydrogen fluoride at 700°C: rare earth element neodymium compound Nd2O3 + 6HF → 2NdF3 + 3H2O. Neodymium (III) chloride NdCl3 Pink-violet hygroscopic crystals, soluble in water. The melting point of chloride is 758°C, the boiling point is 1690°C, and the density is 4.134 g/cm3. Neodymium chloride is obtained by reacting a mixture of chlorine and carbon tetrachloride with neodymium oxide or oxalate at temperatures above 200°C. When interacting with hydrogen bromide and hydrogen iodide, neodymium chloride easily transforms into the corresponding halide and can form hydrates. Anhydrous chloride is used to obtain neodymium metal by the metallothermic method. Neodymium (III) hydroxide Nd(OH)3 When alkali solutions are added to neodymium salts, either basic salts or hydroxide precipitate: (NO3)3 + 2KOH → Nd(OH)2NO3 + 2KNO3(NO3)3 + 3KOH → Nd(OH)3↓ + 3KNO3. Neodymium hydroxide is insoluble and weakly basic. Therefore, it does not dissolve in dilute alkalis, but easily dissolves in acids to form salts. In concentrated alkali solutions, although dissolution occurs with the formation of salts such as MNdO2, these salts are immediately hydrolyzed by water. Consequently, neodymium hydroxide is a weakly amphoteric compound with a sharp predominance of basic properties. Neodymium complex compounds Neodymium is capable of forming complex compounds. The coordination numbers are 6-12, this is explained by the participation of f-orbitals in the formation of bonds. Neodymium forms stable complex compounds with polydentate ligands. Complexation with monodentate ligands is not typical for neodymium. In melts, neodymium forms Na3 hexafluoride. In aqueous solutions, it forms strong complexes with both inorganic and organic anions (ligands). Neodymium is also characterized by the formation of crystalline hydrates. Nd3+ ions in aqueous solutions are hydrated and exhibit a coordination number of 9, and in solid hydrated salts isolated from aqueous solutions - up to 10-12. The high coordination number is also associated with the presence of an unfilled 4f sublevel, on which there are still many vacant places. Application Neodymium has quite a wide range of practical applications, as it is accessible and cheap. In a natural mixture with praseodymium (didimium), it is used in the manufacture of glasses for safety glasses that block ultraviolet rays, which is especially important for welders, metallurgists, glassblowers (when welding glass, the yellow rays of sodium are especially bright), etc. Glasses with 4.3 % addition of neodymium oxide have Alexandrite effect . Neodymium glass can change color depending on the lighting. It is used to make beautiful vases and art pieces, as high concentrations of neodymium oxide give the glass a bright red hue. Neodymium glass is also used in laser technology. The Nd3+ ion produces laser radiation in the infrared region of the spectrum. For special glasses, extremely high purity neodymium oxide is obtained - 99.996%. Neodymium oxide has a complex of excellent physical and chemical properties and is quite affordable. It finds important application in electrical devices as a dielectric, which has a minimal coefficient of thermal expansion. Neodymium itself is also widely used. It has a better effect than other lanthanides on the properties of magnesium, aluminum and titanium alloys, increasing their strength and heat resistance. Reasons for the effective action of neodymium on magnesium alloys: 1.Neodymium has maximum solubility in magnesium, which contributes to the greatest effect of hardening the alloy as a result of heat treatment. 2.The rate of diffusion of neodymium in magnesium, compared to other studied rare earth metals, turns out to be the smallest - this causes a lower rate of softening of the alloy at elevated temperatures, and, consequently, higher heat resistance. The addition of 5% neodymium to aluminum increases the hardness and tensile strength of the alloy from 5 to 10 kg/mm2. Between these elements in the melt, a chemical interaction occurs with the formation of neodymium intermetallic compounds NdAl2 and NdAl4. The addition of 1% neodymium to titanium increases the tensile strength to 48-50 kg/mm2 (for pure titanium it is 32 kg/mm2), while the same addition of cerium only increases to 38-40 kg/mm2. Neodymium is also used in laser technology. The concentration of Nd3+ ions in glasses intended for this purpose reaches 6%. Glasses used as laser materials have two undeniable advantages: a high concentration of active particles and the ability to manufacture large-sized active elements. The components of such glasses are especially carefully cleaned from impurities of copper, iron, nickel, cobalt, as well as rare earth metals - samarium, dysprosium and praseodymium. Yttrium aluminum garnets activated by neodymium are also widely used as laser materials. Neodymium lasers are used in controlled fusion experiments. Powerful neodymium lasers are promising as one of the important elements of satellite communications. Conclusion Recently, the areas of practical application of lanthanides, including neodymium, have expanded significantly. The element with serial number 60 has a set of unique properties, therefore it is widely used in technology, metallurgy, glass, ceramics and other industries. But there are two factors that hinder the expansion of the range of applications of neodymium and other rare earth elements: the high cost of their pure preparations and insufficient knowledge of individual properties, which hinders their use in practice. Therefore, at present it is necessary to actively study the properties of lanthanides, and perhaps in the coming years new unexpected ways of their application will be discovered. Bibliography 1.Shalinets A. B. Heralds of the atomic age. Elements of group III of the periodic table of D. I. Mendeleev. A manual for students. - M., Education , 1975. - 192 p. .Popular library of chemical elements: In 2 books. / [Comp. V. V. Stanzo, M. B. Chernenko]. - 3rd ed., rev. and additional - M.: Nauka, 1983. .Book 2. Silver - Nilsborium and beyond. 1983. - 572 p. .Reactions of inorganic substances: reference book / R. A. Lidin, V. A. Molochko, L. L. Andreeva; edited by R. A. Lidina. - 2nd ed., revised. and additional - M.: Bustard, 2007. - 637 p. .Constants of inorganic substances: reference book / R. A. Lidin, V. A. Molochko, L. L. Andreeva; edited by R. A. Lidina. - 2nd ed., revised. and additional - M.: Bustard, 2006. - 685 p. .Trifonov D. N. Rare earth elements. - M., 1960. - 134 p. .Akhmetov N. S. General and inorganic chemistry. Textbook for universities. - 4th ed., rev. - M.: Higher. school, ed. center Academy, 2001. - 743 pp., ill.
1.14 (Pauling scale)
Nd←Nd 3+ −2.32V
Nd←Nd 2+ −2.2V
(first electron)
7.1 kJ/mol
289 kJ/mol
hexagonal
(300 K) (16.5) W/(m K)
| 60 | |
| 4f 4 6s 2 | |
origin of name
Being in nature
Place of Birth
Prices
Prices for neodymium with a purity of 99-99.9% in 2011 were about 110 US dollars per 1 kilogram, depending on the production technology used and the country of origin, as well as on the final form of the finished product and the scope of its application and use.
In 2014, the price of 99% pure neodymium was approximately US$70 per 1 kg.
Application
Neodymium is one of the most widely used metals from the lanthanide group, along with samarium, cerium, lanthanum, etc.
Very important areas of application of neodymium are:
- alloying special structural alloys and steels (modification of high-quality steels), neodymium in the form of an additive of 1.5% increases the strength of pure titanium by one and a half times and therefore serves for its alloying.
- production of powerful permanent magnets (neodymium-yttrium-cobalt, neodymium-iron-boron),
Neodymium compounds are used in agriculture (seed treatment to accelerate germination and productivity).
Doping with neodymium significantly increases the strength of thermoelectric materials based on tellurides and selenides of bismuth and antimony and increases the thermo-EMF of these materials. There is an indication that doping thermoelectric alloys of the bismuth-tellurium-cesium system with neodymium also increases their strength, thermo-emf and temporary stability.
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Notes
Links
| Periodic table of chemical elements by D. I. Mendeleev | ||||||||||||||||||||||||||||||||
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| Uut | Uup | Uus | Semimetals | |||||||||||||||||||||||||||||
Excerpt characterizing Neodymium
The singers had just finished when more and more toasts followed, during which Count Ilya Andreich became more and more emotional, and even more dishes were broken, and even more shouting. They drank to the health of Bekleshov, Naryshkin, Uvarov, Dolgorukov, Apraksin, Valuev, to the health of the elders, to the health of the manager, to the health of all club members, to the health of all club guests, and finally, separately to the health of the founder of the dinner, Count Ilya Andreich. At this toast, the count took out a handkerchief and, covering his face with it, completely burst into tears.Pierre sat opposite Dolokhov and Nikolai Rostov. He ate a lot and greedily and drank a lot, as always. But those who knew him briefly saw that some big change had taken place in him that day. He was silent the entire time of dinner and, squinting and wincing, looked around him or, stopping his eyes, with an air of complete absent-mindedness, rubbed the bridge of his nose with his finger. His face was sad and gloomy. He seemed to not see or hear anything happening around him, and was thinking about something alone, heavy and unresolved.
This unresolved question that tormented him, there were hints from the princess in Moscow about Dolokhov’s closeness to his wife and this morning the anonymous letter he received, in which it was said with that vile playfulness that is characteristic of all anonymous letters that he sees poorly through his glasses, and that his wife’s connection with Dolokhov is a secret only to him. Pierre decidedly did not believe either the princess’s hints or the letter, but he was now afraid to look at Dolokhov, who was sitting in front of him. Every time his gaze accidentally met Dolokhov’s beautiful, insolent eyes, Pierre felt something terrible, ugly rising in his soul, and he quickly turned away. Unwittingly remembering everything that had happened with his wife and her relationship with Dolokhov, Pierre saw clearly that what was said in the letter could be true, could at least seem true if it did not concern his wife. Pierre involuntarily recalled how Dolokhov, to whom everything was returned after the campaign, returned to St. Petersburg and came to him. Taking advantage of his carousing friendship with Pierre, Dolokhov came directly to his house, and Pierre accommodated him and lent him money. Pierre recalled how Helen, smiling, expressed her displeasure that Dolokhov lived in their house, and how Dolokhov cynically praised the beauty of his wife, and how from that time until his arrival in Moscow he was not separated from them for a minute.
“Yes, he is very handsome,” thought Pierre, I know him. It would be a special delight for him to dishonor my name and laugh at me, precisely because I worked for him and looked after him, helped him. I know, I understand what salt this should give to his deception in his eyes, if it were true. Yes, if it were true; but I don’t believe, I don’t have the right and I can’t believe.” He recalled the expression that Dolokhov's face took on when moments of cruelty came over him, like those in which he tied up a policeman with a bear and set him afloat, or when he challenged a man to a duel without any reason, or killed a coachman's horse with a pistol. . This expression was often on Dolokhov's face when he looked at him. “Yes, he’s a brute,” thought Pierre, it doesn’t mean anything to him to kill a man, it must seem to him that everyone is afraid of him, he must be pleased with this. He must think that I am afraid of him too. And really I’m afraid of him,” thought Pierre, and again with these thoughts he felt something terrible and ugly rising in his soul. Dolokhov, Denisov and Rostov were now sitting opposite Pierre and seemed very cheerful. Rostov chatted merrily with his two friends, one of whom was a dashing hussar, the other a famous raider and rake, and occasionally glanced mockingly at Pierre, who at this dinner impressed with his concentrated, absent-minded, massive figure. Rostov looked at Pierre unkindly, firstly, because Pierre, in his hussar eyes, was a rich civilian, the husband of a beauty, generally a woman; secondly, because Pierre, in the concentration and distraction of his mood, did not recognize Rostov and did not respond to his bow. When they began to drink the sovereign's health, Pierre, lost in thought, did not get up and take the glass.
- What are you doing? - Rostov shouted to him, looking at him with enthusiastically embittered eyes. - Don't you hear? health of the sovereign emperor! - Pierre sighed, stood up obediently, drank his glass and, waiting until everyone sat down, turned to Rostov with his kind smile.
“But I didn’t recognize you,” he said. - But Rostov had no time for that, he shouted hurray!
“Why don’t you renew your acquaintance,” Dolokhov said to Rostov.
“God be with him, you fool,” said Rostov.
“We must cherish the husbands of pretty women,” Denisov said. Pierre did not hear what they said, but he knew that they were talking about him. He blushed and turned away.
“Well, now for the health of beautiful women,” said Dolokhov, and with a serious expression, but with a smiling mouth at the corners, he turned to Pierre with a glass.
“For the health of beautiful women, Petrusha, and their lovers,” he said.
Pierre, with his eyes downcast, drank from his glass, without looking at Dolokhov or answering him. The footman who was handing out Kutuzov's cantata put the sheet of paper on Pierre, as a more honored guest. He wanted to take it, but Dolokhov leaned over, snatched the piece of paper from his hand and began to read. Pierre looked at Dolokhov, his pupils sank: something terrible and ugly, which had been bothering him throughout dinner, rose up and took possession of him. He leaned his entire corpulent body across the table: “Don’t you dare take it!” - he shouted.
Hearing this cry and seeing who it referred to, Nesvitsky and the neighbor on the right side turned to Bezukhov in fear and haste.
- Come on, come on, what are you talking about? - whispered frightened voices. Dolokhov looked at Pierre with bright, cheerful, cruel eyes, with the same smile, as if he was saying: “But this is what I love.” “I won’t,” he said clearly.
Pale, with a trembling lip, Pierre tore off the sheet. “You... you... scoundrel!.. I challenge you,” he said, and moving his chair, he stood up from the table. At that very second that Pierre did this and uttered these words, he felt that the question of his wife’s guilt, which had been tormenting him these last 24 hours, was finally and undoubtedly resolved in the affirmative. He hated her and was forever separated from her. Despite Denisov’s requests that Rostov not interfere in this matter, Rostov agreed to be Dolokhov’s second, and after the table he talked with Nesvitsky, Bezukhov’s second, about the conditions of the duel. Pierre went home, and Rostov, Dolokhov and Denisov sat in the club until late in the evening, listening to gypsies and songwriters.
“So see you tomorrow, in Sokolniki,” said Dolokhov, saying goodbye to Rostov on the porch of the club.
- And are you calm? - asked Rostov...
Dolokhov stopped. “You see, I’ll tell you in a nutshell the whole secret of the duel.” If you go to a duel and write wills and tender letters to your parents, if you think that they might kill you, you are a fool and are probably lost; and you go with the firm intention of killing him, as quickly and surely as possible, then everything will be fine. As our Kostroma bear hunter used to tell me: how can one not be afraid of a bear? Yes, as soon as you see him, and the fear passes, as if it didn’t go away! Well, so am I. A demain, mon cher! [See you tomorrow, my dear!]
The next day, at 8 o’clock in the morning, Pierre and Nesvitsky arrived at the Sokolnitsky forest and found Dolokhov, Denisov and Rostov there. Pierre had the appearance of a man busy with some considerations that were not at all related to the upcoming matter. His haggard face was yellow. He apparently didn't sleep that night. He looked around absently and winced as if from the bright sun. Two considerations exclusively occupied him: the guilt of his wife, of which, after a sleepless night, there was no longer the slightest doubt, and the innocence of Dolokhov, who had no reason to protect the honor of a stranger to him. “Maybe I would have done the same in his place,” Pierre thought. I probably would have done the same thing; Why this duel, this murder? Either I kill him, or he will hit me in the head, elbow, knee. “Get out of here, run away, bury yourself somewhere,” came to his mind. But precisely in those moments when such thoughts came to him. With a particularly calm and absent-minded look, which inspired respect in those who looked at him, he asked: “Is it soon, and is it ready?”
