Chinese name: gadolinium English name: gadolinium alias: gadolinium rod gadolinium ingot molecular weight: 157.25 CAS registration number: 7440-54-2 EINECS registration number: 231-kloc-0/62-2 melting point:13/kloc-. 790 1kg/m3？ Appearance: silvery white rare earth metal field: rare earth substance element symbol: brief history of Gd discovery, mineral distribution, physical properties, chemical properties, uses, application fields, specific uses and preparation methods. Gadolinium in the brief history of discovery was discovered by Charles Garissad de Marignac in 1880. He always suspected that the neodymium praseodymium reported by Karl Mosander was not a new element, but a mixture. His conjecture was confirmed by Marc Delafontaine and Paul-Emile LeCoq de Boi in Paris. It is reported that its spectral lines will change from different sources. In fact, in 1879, they have separated samarium from some neodymium praseodymium, which is extracted from niobium and yttrium minerals in the Urals Mountains. 1880, Marignac extracted another new rare earth from didymium, Paul-? 1886 also realized Mile Lecoq de Boi *** audran, called gadolinium. Since Mosander C.G. discovered lanthanum, erbium and terbium successively, chemists all over the world have paid special attention to separating new elements from the discovered rare earth elements. In the second year after the discovery of samarium, in 1880, the Swiss scientist Marinak discovered two new elements, which were named γ α and γ β respectively. It was later proved that γ β and samarium are the same element. 1886, Boisbaudran made pure gamma alpha, which was determined to be a new element. Named gadolinium, element symbol Gd. This is in memory of Finnish mineralogist J. Gardolin. Gadolinium, samarium, praseodymium and neodymium were all separated from neodymium and praseodymium, which were considered as rare earth elements at that time. Because of their discovery, dysprosium is no longer preserved. It was their discovery that opened the third door and the third stage of the discovery of rare earth elements. But this is only half of the third stage. Specifically, it should be to open the door of cerium or complete the separation of cerium, and the other half will be to open the door of yttrium or complete the separation of yttrium. At present, there are more than 250 kinds of rare earth minerals and minerals containing rare earth elements, more than 60 kinds of minerals with high rare earth elements, and less than 10 kinds of minerals with industrial value. China is extremely rich in rare earth resources, and its characteristics can be summarized as: large reserves, complete varieties, high content of valuable elements and wide distribution. China's rare earth industrial reserve (calculated by oxide) is 2.2 times that of foreign rare earth industrial reserve. Foreign rare earth resources are concentrated in the United States, India, Brazil, Australia, the Soviet Union and other countries, and industrial reserve (in terms of oxides) is 70 1. 1 1 10,000 tons. Physical Properties Gadolinium is a silvery white metal with ductility, melting point 13 13℃, boiling point 3266℃ and density of 7.9004g/cm & amp； sup3。 Gadolinium is magnetic at room temperature. Gadolinium is relatively stable in dry air and loses its luster in humid air. Gadolinium has the highest thermal neutron capture surface and can be used as reactor control material and protection material. Gadolinium salt magnetized refrigeration can obtain ultra-low temperature close to absolute zero. 1880, Mari Gnacke of Switzerland separated samarium into two elements, one of which was confirmed by Sorett and the other by Boyce Baudelaire. 1886, Nakel, Mali. In memory of Gadolin, the discoverer of yttrium and the pioneer of rare earth research, gadolinium will play an important role in modern scientific and technological innovation. Metal gadolinium CASNo. : 7440-54-2 Element name: gadolinium content in the sun: (ppm): 0.002 element content in seawater: (ppm): 0.0000006 element content in the surface crust of the Pacific Ocean: (ppm): 7.7 element atomic weight: 157.25 oxidation state: main GD+2, The unit cell parameters of metallic gadolinium: a = 363.6pmb = 363.6pmc = 578.26pmα = 90β = 90γ = 655Gd-Fe alloy M-M+592.5m+-m2+1 67m2+-m3+/kloc. S2 extranuclear electron configuration: 2,8,18,25,9, 2 Nuclear charge number: 64 Crystal type: close-packed hexagonal isotopes and radiation: GD-148 [75y] GD-150 [1800000y] GD-152 (magnification α [1) Kloc-0/ element density: 7.895 g/cm3 Element melting point:131.0℃ Element boiling point: 3233.0℃ Atomic radius: 2.54 angstrom ion radius: 0.938(+3) angstrom valence radius:/. Mol: 10.050 Vaporization heat: (kJ/mol): 359.40 Element content in the universe: (ppm): 0.002 atomic volume: (cm3/mol): 19.9 Chemical properties can react slowly with water; Soluble in acid to form the corresponding salt. Elemental uses: It is often used as neutron absorbing material in atomic reactors. It is also used in microwave technology and fluorescent powder of color TV. Darken in humid air. Soluble in acid and insoluble in water. The oxide is white powder. Salt is colorless. It has good superconductivity, high magnetic moment and Curie point at room temperature. Gadolinium has the following isotopes: 152Gd, 154Gd~ 158Gd, 160Gd. The important property of gadolinium in the application field is that there is one electron in each of the seven orbits, which is the largest number of unpaired electrons in rare earth elements. Depending on this unpaired electron, the magnetic moment is the largest, which can be expected to be effectively utilized. Medical field: In medical application, the complex of gadolinium-diethylene diamine pentaacetic acid (DTPA) can be used as a regulator of MRI (magnetic resonance imaging diagnosis), just as barium is used as an X-ray contrast agent. That is to say, the water around gadolinium is affected by the magnetic field torque of gadolinium nucleus, showing different properties from the unaffected water. The use of control pictures is beneficial to the diagnosis of diseases. Industrial field: a well-known industrial technology is called magnetic freezing, which generates heat when it becomes a magnet under the action of a magnetic field, and removes the endothermic property when the magnetic field disappears to cool it. Small and efficient refrigerators can be made. In the bubble memory device, gadolinium-potassium-garnet is used as the medium. Bubble memory is to add a magnetic field in the vertical direction of matter, make it become a cylindrical magnetic field, strengthen the magnetic field, and soon the magnetic field will disappear. The bubble storage device can be used to store information, which is generally used for information collection. Other uses of gadolinium are optical fibers and optical disks, such as terbium and dysprosium. Magneto-optical recording uses light to read magnetized and unmagnetized parts, which has the characteristics of high density and rewritable recording. Nuclear energy field: In the atomic energy industry, isotopes of europium and gadolinium are used as control rods and neutron absorbers for light water reactors and fast breeder reactors. Gadolinium is a strong reaction of all elements to thermal neutrons, which can be used not only for the control of atomic reactors, but also to absorb invisible neutrons and make them glow together with gadolinium, and can be used as a sensitive fluorescent agent for X-ray films. Specific uses Its main uses are: (1) Its water-soluble paramagnetic complex can improve the MRI signal of human body in medical treatment. (2) Its sulfur oxide can be used as matrix grid of oscilloscope tube and X-ray fluorescent screen with special brightness. (3) Gadolinium in gadolinium gallium garnet is an ideal single-substrate bubble memory. (4) When there is no Camotte cycle restriction, it can be used as a solid magnetic refrigeration medium. (5) Used as an inhibitor to control the chain reaction level of nuclear power plants and ensure the safety of nuclear reactions. (6) Used as an additive for Sm-Co magnets to ensure that the performance does not change with the temperature. In addition, the use of gadolinium oxide together with lanthanum is helpful to change the glass transition zone and improve the thermal stability of glass. Gadolinium oxide can also be used to make capacitors and X-ray intensifying screens. At present, international efforts are being made to develop the application of gadolinium and its alloys in magnetic refrigeration, and breakthroughs have been made. At room temperature, magnetic refrigerators using superconducting magnets, metallic gadolinium or their alloys as refrigeration media have been developed. The preparation method is gadolinium, which comes from gadolinium ore. It can be prepared by reducing gadolinium fluoride GdF3 2H2O with calcium.