Complaint
Gadolinium is a silver-white metal, malleable, with a melting point of 1313°C, a boiling point of 3273°C, and a density of 7.901g/m3. Gadolinium is magnetic at room temperature. Gadolinium is stable in dry air and loses its luster in wet air. Gadolinium has the highest thermal neutron capture surface and can be used as reactor control material and protective material. The ultra-low temperature close to absolute zero can be obtained by magnetizing refrigeration with gadolinium salt. In 1880, Marignac of Switzerland separated "samarium" into two elements, one of which was confirmed by Sorit to be samarium, the other element was confirmed by Bois Baudele's work. In 1886, Marignac honored the discoverer of yttrium and the pioneer of rare earth research Dutch chemist Gado Linium, The name of this new element is gadolinium. Gadolinium will play an important role in modern technological innovation.
CAS number: 7440-54-2
Element name: gadolinium
Element content in the Sun (ppm) : 0.002
Element content in seawater (ppm) : Pacific Surface 0.0000006
Crustal content (ppm) : 7.7
Atomic weight of element: 157.25
Main oxidation states: +2, +3
Crystal structure: the cell is hexagonal.
Cell parameters:
a = 363.6pm
b = 363.6pm
c = 578.26pm
Alpha is equal to 90 degrees
Beta = 90°
Gamma is equal to 120 degrees
Vickers Hardness: 570MPa
The speed at which sound travels: (m/s) 2680
Ionization energy (kJ/mol) :
M-M + 592.5
M+ - M2+ 1167
M2+ - M3+ 1990
M3+ - M4+ 4250
Relative atomic mass: 157.25
Electronegativity: 1.2
Outer electron shell configuration: 4f75d16s2
Electron configuration: 2,8,18,25,9,2
Nuclear charge: 64
Elemental density: 7.901g/cm3
Elemental melting point: 1313ºC
Elemental boiling point: 3273ºC
Atomic radius: 2.54 angstroms
Ionic radius: 0.938(+3) angstroms
Covalent radius: 1.61 angstroms
Bulk elastic modulus Gpa: 37.9
Enthalpy of atomization kJ/mol @25ºC : 352
Heat capacity J/(mol·K) : 37.03
Conductivity 106/(cm·Ω) : 0.00736
Thermal conductivity W/(m·K) : 10.6
Heat of melting (kJ/mol) : 10.050
Heat of vaporization (kJ/mol) : 359.40
Element content in the universe (ppm) : 0.002
Atomic volume (cm3/mol) : 19.9
Chemical properties editor
Reacts slowly with water; Dissolves in acid to form the corresponding salt.
Use of elements: Commonly used as neutron-absorbing materials in atomic reactors. Also used in microwave technology, color television phosphors.
Darkening in the humid air. Soluble in acid, insoluble in water. The oxide is white powdery. Salts are colorless. It has good superconducting electric properties, high magnetic moment and Curie point at room temperature. Gadolinium has the following isotopes: 152Gd, 154Gd~158Gd, 160Gd.
Application editing broadcast
Application field
Gadolinium's important property is that it has one electron in each of its seven orbitals, the largest number of unpaired electrons in a rare earth element. The magnetic torque that is dependent on this unpaired electron is the largest, and it can be expected that this property can be utilized effectively.
Medical field:
For medical applications, the complex of gadolinium - diethylenediamine pentaacetic acid (DTPA) can be used just as barium, an X-ray contrast agent, as a regulator of image intensity in MRI (magnetic resonance imaging diagnosis). That is, using the fact that the water around gadolinium is affected by the magnetic torque of the gadolinium nucleus, showing different properties than the water that is not affected, the use of control images facilitates the diagnosis of the condition [2].
Industrial field: The well-known industrial technology known as magnetic freezing is to heat up when it is changed into a magnet by a magnetic field, and the properties of absorbing heat when the magnetic field is removed are used for cooling. You can make small, efficient refrigerators.
Gadolinium - potassium - garnet is used as a media substance in a bubble memory device. Magnetic bubble memory is to add a magnetic field to the vertical direction of a material, so that it becomes a cylindric magnetic field, strengthen the magnetic field, and soon produce the phenomenon that the magnetic field disappears. Magnetic bubble memory device can store information, generally used for information collection.
Other uses of gadolinium are in optical fibers, optical disks, like terbium and dysprosium. Opto-magnetic recording is used to read the magnetized and unmagnetized areas with light instead of magnetic. It has the characteristics of high density and rewriting records.
Nuclear energy: In the atomic energy industry, the large neutron absorption cross sections of isotopes of europium and gadolinium are used as control rods and neutron absorbent for light water reactors and fast neutron breeder reactors [3].
The use of gadolinium is characterized by the strong reaction of all elements to thermal neutrons. In addition to the control of atomic reactors, invisible neutrons can be absorbed by gadolinium and made to emit light as a fluorescent agent for sensitizing X-ray film. [4]
Specific use
Its main uses are:
(1) Its water-soluble paramagnetic complex can improve human nuclear magnetic resonance (NMR) imaging signal medically [5].
(2) The sulfur oxide can be used as a substrate grid for special brightness oscilloscopes and X-ray fluorescent screens.
(3) Gadolinium in gadolinium gallium garnet is ideal as a single substrate for bubble memory memory.
(4) It can be used as solid magnetic cooling medium without Camot cycle limitation.
(5) Used as an inhibitor to control the chain reaction level of nuclear power plants, so as to ensure the safety of nuclear reactions.
(6) Used as an additive for samarium cobalt magnets to ensure that the properties do not change with temperature.
In addition, gadolinium oxide is used with lanthanum to help change the vitrification zone and improve the thermal stability of the glass. Gadolinium oxide can also be used to make capacitors and X-ray sensitizing screens. In the world, efforts are being made to develop the application of gadolinium and its alloys in magnetic cooling, and breakthrough progress has been made. Magnetic refrigerators using superconducting magnets, metal gadolinium or its alloys as cooling media at room temperature have come out.
Preparation method edit broadcast
Gadolinium, derived from silicon berylolinium ore. It can be prepared from gadolinium fluoride GdF3·2H2O reduced by calcium
