1. Scandium Pinyin: Kang Traditional Character: Scandium
Radical: bell, external strokes: 4, total strokes: 9; Traditional radicals: gold, external strokes: 4, total strokes: 12.
Wu Bi 86:QYMN Wu Bi 98:QYWN Cang Xie: XCYHN
Number of strokes: 311154135 Four-corner number: 807 17 UniCode:CJK unified Chinese character U+94AA.
Basic word meaning
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scandium (Sc)
Element Attribute Data (Scandium)
kàngㄎㄤˋ
A metallic element, silvery white, soft and soluble in acid. Generally, it will oxidize rapidly in the air and lose its luster. It mainly exists in rare scandium yttrium stone. Can be used for manufacturing special glass and light high-temperature resistant alloy.
Chinese-English translation
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scandium (Sc)
scandium (Sc)
English
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Use scandium
Detailed word meaning
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scandium (Sc)
Scancon
A white trivalent metallic element. Atomic number 2 1[ Scanning]-element symbol sc
Basic word meaning
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scandium (Sc)
Scancon
scandium (Sc)
In elemental chemistry, a series of metallic elements with very similar properties are called rare earth elements. This series includes 15 Lanthanide elements-lanthanum (la), Cerium (ce), Praseodymium (pr), neodymium (Nd), promethium (Pm), samarium (Sm), Europium (eu), gadolinium (Gd) and terbium. And two lighter elements with similar properties: scandium and yttrium. This series of elements was originally found in rare minerals produced in Sweden. "Earth" is a general term for metal oxides that were insoluble in water at that time, hence the name "rare earth". Among these seventeen elements, scandium ranks first, and its atomic number is only 2 1. But as far as discovery is concerned, scandium is almost one hundred years behind its neighbors in the periodic table of elements. Even among rare earths, scandium was not discovered early, ranking seventh after yttrium, cerium, lanthanum, erbium, terbium and ytterbium. As the lightest pioneer, he appeared really late. There is a simple reason. The content of scandium in the earth's crust is not high, only 5* 10-6, which is equivalent to 5 grams per ton of earth's crust material (a small piece of Dove chocolate or white rabbit toffee), which is not only much lower than other light elements, but also only medium among the whole rare earth elements, only about110 of his richest brother cerium. In addition, rare earth elements feel a bit like collective leadership. Their mine seems to be holding a Politburo meeting. As long as there is a meeting, these elements tend to attend the meeting. Therefore, it is not easy to find our scandium from mixed deposits. However, although never discovered, the existence of this element has been predicted. In the first edition of the periodic table of elements given by Mendeleev in 1869, there is a vacancy with an atomic weight of 45 behind calcium. Later, Mendeleev temporarily put this element after calcium and gave some physical and chemical properties of this element. However, this prophecy, like writing paper in a drifting bottle, was temporarily lost in the academic ocean of Wang Yang.
Mendeleev's prediction didn't get people's attention, but in the late19th century, the study of rare earth elements became a craze. One year before scandium was discovered, de Marignac of Switzerland obtained a white oxide different from erbium soil by partially decomposing nitrate in rose red erbium soil. He named this oxide ytterbium soil, which is the sixth discovery of rare earth elements. At that time, the old horse had few samples at hand, so it was suggested that scientists with sufficient erbium soil should prepare more ytterbium soil and study its properties. At that time, Nelson of Uppsala University in Sweden happened to have samples of erbium soil at hand, so he wanted to purify erbium soil according to Malinak's method and accurately measure the atomic weights of erbium and ytterbium (because he was now focusing on accurately measuring the physical and chemical constants of rare earth elements to verify the periodic laws of elements). After partial decomposition of 13, he got 3.5g pure ytterbium soil. But at this time, something strange happened. Marinak gave the atomic weight of ytterbium as 172.5, while Nelson got only 167.46. Nelson is keenly aware that there may be some light elements in it, so that the determination of atomic weight is no longer accurate. So he continued to treat ytterbium soil with the same process, and finally when only one tenth of the sample was left, the measured atomic weight dropped to134.75; At the same time, some new absorption lines were found in the spectrum. Nelson's judgment was correct, so he got the right to name his child. He named Scandium after his hometown Scandinavia. 1879 officially published the research results. He also mentioned many chemical properties of scandium salt and scandium soil in his paper. But in this paper, he did not give the exact atomic weight of scandium, nor did he determine the position of scandium in the element cycle.
Cliff, Nelson's good friend and teacher at Uppsala University, also did the work together. Starting from erbium soil, he excluded erbium soil as a large number of components, then separated ytterbium soil and scandium soil, and found two new rare earth elements, holmium and thulium, from the residue. As a by-product, he purified scandium soil and further understood the physical and chemical properties of scandium. In this way, the drift bottle released by Mendeleev was finally fished up by Cliff after sleeping for ten years. He realized that scandium was Mendeleev's boron. Let's see if some chemical properties of scandium are consistent with the predictions written on the old parchment in the bottle.
Potassium boron scandium
Atomic weight 44 45. 1 (Cliff, 1879)
Atomic volume: (cc/mol) 15.0
Content in the shell: (ppm) 16
Element content in the sun: (ppm) 0.04
Element content in seawater: (ppm)
Pacific surface 0.00000035
44.9438+00 (IUPAC, Modern)
Compounds in the form of Eb2O3 can be formed, with a specific gravity of 3.5, which is more alkaline than alumina and weaker than yttrium oxide and magnesium oxide. It is doubtful whether it can react with ammonium chloride. Sc2O3, with a specific gravity of 3.86, is more alkaline than alumina and weaker than yttrium oxide and magnesium oxide, and does not react with ammonium chloride.
Salt is colorless and forms colloidal precipitation with potassium hydroxide and sodium carbonate, so it is difficult for all kinds of salts to crystallize well. Scandium salt is colorless, forms colloidal precipitation with potassium hydroxide and sodium carbonate, and sulfate is extremely difficult to crystallize.
Carbonate is insoluble in water and may form basic carbonate precipitation. Scandium carbonate is insoluble in water and easy to remove carbon dioxide.
Double sulfate may not form alum. Scandium sulfate double salt will not become alum.
EbCl3, an anhydrous chloride, is less volatile than aluminum chloride and easier to hydrolyze than magnesium chloride. The sublimation temperature of ScCl3 is 850oC, while that of AlCl3 is 100oC, which is hydrolyzed in aqueous solution.
Eb is not found in the spectrum. The spectrum can't find Sc.
In that place, not only do you know nothing about the electronic shell structure of elements (even electrons were discovered by 1899), but even authoritative chemists like Duma are skeptical about atomism. Being able to describe the nature of an undiscovered element so accurately really makes readers feel a faint coolness in their backs.
Scandium Mendeleev (1834- 1907)
Nelson (1840- 1899) Cliff (1840- 1905)
2. Children of Light
For a long time after scandium was discovered, its use was not shown because it was difficult to prepare. With the improvement of the separation method of rare earth elements, there has been a quite mature technological process for purifying scandium compounds. Because scandium hydroxide is the weakest compared with yttrium and lanthanide elements, when the treatment of scandium-containing rare earth mixed ore is transferred to the solution and treated with ammonia water, scandium hydroxide will precipitate first, so it is easy to separate it from rare earth elements by "fractional precipitation". Another method is to separate scandium nitrate by polarization decomposition, because scandium nitrate is the easiest to decompose and can achieve the purpose of separating scandium. In addition, the comprehensive recovery of associated scandium in uranium, thorium, tungsten and tin deposits is also one of the important sources of scandium.
Monolith in Heixi Gold Mine
Gadolinite uranium ore
After the pure scandium compound is obtained, it is transformed into ScCl3, melted with KCl and LiCl***, electrolyzed with molten zinc as cathode, and scandium is precipitated on the zinc electrode, and then the zinc is evaporated to obtain metallic scandium. This is a light silvery white metal with very active chemical properties, which can react with hot water to generate hydrogen. So the scandium metal you see in the picture is sealed in a bottle and protected by argon, otherwise scandium will quickly form a dark yellow or gray oxide layer and lose that shiny metallic luster.
Interestingly, the uses of scandium (as the main working substance, not for doping) are concentrated in a very bright direction, and it is not an exaggeration to call him the son of light.
The first magic weapon of scandium is called scandium sodium lamp, which can bring light to thousands of families. This is a metal halide electric light source: the bulb is filled with sodium iodide and scandium iodide, and scandium and sodium foil are added at the same time. During high voltage discharge, scandium ions and sodium ions respectively emit light with their characteristic emission wavelengths. The spectral lines of sodium are two famous yellow lights at 589.0 nm and 589.6nm, while scandium emits a series of near ultraviolet and blue lights at 36 1.3~424.7nm, because they are complementary colors. Because scandium sodium lamp has the characteristics of high luminous efficiency, good light color, power saving, long life and strong fog breaking ability, it can be widely used in TV camera and square, gymnasium and road lighting, and is called the third generation light source. In China, this kind of lamp is gradually popularized as a new technology, but in some developed countries, it was widely used as early as the early 1980s. The second magic weapon of scandium is solar photovoltaic cells, which can collect light scattered on the ground and convert it into electric energy to promote human society. Scandium is the best barrier metal in metal-insulator-semiconductor silicon photovoltaic cells and solar cells. His third magic weapon is called gamma ray source, which can shine by itself, but this kind of light is not received by our naked eyes, and it is a high-energy photon stream. We usually extract 45Sc from minerals, which is the only natural isotope of scandium. Each nucleus of 45Sc has 2 1 proton and 24 neutrons. If scandium is put in a nuclear reactor for 7749 days like a monkey in an alchemy furnace of Taishang Laojun, and it absorbs neutron radiation, then 46Sc with one more neutron in the nucleus is born. 46Sc is an artificial radioisotope, which can be used as gamma ray source or tracer atom, and can also be used for radiotherapy of malignant tumors. There are also applications such as yttrium gallium scandium garnet laser, scandium fluoride glass infrared fiber and scandium-plated cathode ray tube on TV. It seems that scandium is born with light.
3. magic seasoning
Some applications of scandium are mentioned above. However, due to the high price, considering the cost, a large number of scandium and scandium compounds are rarely used in industrial products, and they are all used as a thin scandium foil in light bulbs. In more fields, scandium and scandium compounds are used as magical seasonings, as if only a little salt, sugar or monosodium glutamate in a chef's hand would make the finishing touch.
In inorganic chemistry, doping is a very important means. When the crystal structure is doped with a small amount of other compounds as the matrix, because the chemical properties of the doped substances are different from the original matrix, various changes and defects will occur in the lattice structure, thus either improving the properties of the original matrix or increasing its original activity. For example, the most familiar P-type and N-type semiconductor raw materials are obtained by adding boron, which leads to holes due to lack of valence electrons, and phosphorus, which generates free electrons due to excess valence electrons, to single crystal silicon with poor conductivity. Our scandium is also an important doping raw material, and many materials have obtained unexpected properties because of scandium doping.
Scandium in elemental form has been widely used in the doping of aluminum alloys. As long as a few thousandths of scandium is added to aluminum, a new phase of Al3Sc will be formed, and the aluminum alloy will be modified, so that the microstructure and properties of the alloy will change obviously. Adding 0.2%~0.4% Sc (this ratio is really similar to that of cooking salt at home, only a little) can increase the recrystallization temperature of the alloy 150~200℃, obviously improve the high-temperature strength, microstructure stability, weldability and corrosion resistance, and also avoid the embrittlement phenomenon that is easy to occur after working for a long time at high temperature. High-strength and high-toughness aluminum alloys, new high-strength and corrosion-resistant weldable aluminum alloys, new high-temperature aluminum alloys and high-strength aluminum alloys for neutron irradiation have very attractive development prospects in the fields of aerospace, aviation, ships, nuclear reactors, light vehicles and high-speed trains. Scandium is also an excellent modifier for iron, and a small amount of scandium can significantly improve the strength and hardness of cast iron. In addition, scandium can also be used as an additive for high temperature tungsten-chromium alloy. Of course, in addition to making wedding dresses for others, scandium is also used in light alloys with high melting point, such as scandium titanium alloy and scandium magnesium alloy, because it has a high melting point and a density close to that of aluminum. However, I'm afraid this rare thing can only be used in space shuttles and rockets. If they are used as bicycle racks, this value may be stolen twenty or thirty times a day.
Scandium is generally used in alloys, and scandium oxides also play an important role in ceramic materials, such as birds of a feather. Tetragonal zirconia ceramic material, which can be used as electrode material of solid oxide fuel cells, has a very special property, and the conductivity of this electrolyte will increase with the increase of temperature and oxygen concentration in the environment. However, the crystal structure of this ceramic material itself cannot exist stably and has no industrial value; It must be doped with some substances that can fix this structure in order to maintain its original properties. Adding 6- 10% scandium oxide is just like concrete structure, which makes zirconia stable on square lattice. There are also high-strength and high-temperature resistant engineering ceramic materials such as silicon nitride as densification agents and stabilizers. Scandium oxide, as a densifier, can form refractory phase Sc2Si2O7 at the edge of fine particles, thus reducing the high-temperature deformation ability of engineering ceramics and improving the high-temperature mechanical properties of silicon nitride better than adding other oxides. Adding a small amount of Sc2O3 to UO2 in high temperature reactor nuclear fuel can avoid lattice transformation, volume increase and cracks caused by UO2' s transformation to U3O8.
Scandium is not unknown in organic chemistry, but it is used as a catalyst in organic reactions. Although it is also a seasoning, it is different from doping in inorganic materials. Sc2O3 can be used for dehydration and deoxidation of ethanol or isopropanol, decomposition of acetic acid, production of ethylene from carbon monoxide and H2, etc. Pt-Al catalyst containing Sc2O3 is an important catalyst in the process of heavy oil hydrofining in petrochemical industry. In the catalytic cracking reaction of cumene, the activity of Sc-Y zeolite catalyst is 1000 times higher than that of aluminum silicate. Compared with some traditional catalysts, scandium catalysts will have a very broad development prospect.
From Nelson's concern about the lack of atomic weight data to today, scandium has only entered people's field of vision for more than one hundred years, but it has been sitting on the bench for almost one hundred years. It was not until the vigorous development of materials science in the late last century that it brought him vitality. Today, rare earth elements, including scandium, have become a hot star in materials science, playing an ever-changing role in thousands of systems, bringing more convenience to our lives every day, and the economic value created is even more incalculable. According to the theory of Yin-Yang and Five Elements, is it true that local gold is born?
Appendix: Characteristics of Scandium
Calcium-scandium-titanium
scandium (Sc)
Yttrium (y)
periodic table of elements
Overall characteristics
Name, symbol and serial number
Scandium, scandium, 2 1
Oxidation state:
Main Sc+2, Sc+3
other
Ionization energy (kJ/mol)
M - M+ 63 1
M+ - M2+ 1235
M2+ - M3+ 2389
M3+ - M4+ 7089
M4+ - M5+ 8844
M5+ - M6+ 10720
M6+ - M7+ 13320
M7+ - M8+ 153 10
M8+ - M9+ 17369
M9+ - M 10+ 2 1740
Cell parameters:
a = 330.9 pm
b = 330.9 pm
c = 527.33 pm
α = 90
β = 90
γ = 120
Series transition metals
Series, Period, Element Partition
Three families, four, d
Density, hardness
2985kg/m3, no data.
Color and appearance
silvery white
Crustal content
5× 10-4 %
Atomic properties
atomic weight
44.9438+00 atomic weight unit
Atomic radius (calculated value)
Afternoon 160( 184)
* * * Price range
Afternoon 144
Van der Waals radius
No data yet.
Jia electronic configuration
[argon ]3d 14s2
Crystal structure: the unit cell is hexagonal.
The electron arrangement of each energy level
2,8,9,2
Oxidation valence (oxide)
3 (weak alkaline)
crystalline structure
hexagon
physical quality
Material state
solid state
melting point
18 14K( 154 1°C)
boiling point
3 103 (2830℃)
molar volume
15.00× 10-6 m3/mol
heat of vapourization
3 14.2 kj/mol
melting heat
14. 1 kj/mol
Steam pressure
22. 1 pa (18 12K)
speed of sound
No data (293. 15K)
Other attributes
electronegativity
1.36 (Pauling scale)
specific heat
568 Joule/(kg kg)
electrical conductivity
1.77× 106/ (m ohm)
conductivity for heat
15.8W/(m g)
the first ionization energy
633. 1 kj/mol
The second ionization energy is 1235.0 kJ/mol.
The third ionization energy is 2388.6 kJ/mol.
The fourth ionization energy is 7090.6 kJ/mol.
The fifth ionization energy is 8843 kJ/mol.
The sixth ionization energy is 10679 kJ/mol.
Seventh ionization energy 133 10 kJ/mol.
The eighth ionization energy is 15250 kJ/mol.
The ninth ionization energy is 17370 kJ/mol.
The tenth ionization energy is 2 1726 kJ/mol.
The most stable isotope
isotope
abundant
half-life period
Decay mode
Decay energy
Megaelectron volt
Decay products
45Sc 100% stable
46Sc artificial
83.79 days β decay
2.367 46Ti
Scandium was discovered by Lars Frederick Nilson in 1879, and its name is Scandinavia (Scandinavia).
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