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About Gadolinium

Gadolinium Bohr

Swiss chemist Jean Charles Galissard de Marignac discovered an oxide of an unknown element in a sample of gadolinite in 1880 and subsequently named the oxide “gadolinia”. The mineral had been named for Finnish chemist and geologist Johan Gadolin, who had discovered the first rare earth element, yttrium, in 1794. Thus gadolinium, named from its oxide, was only the second element to be named after an individual--the first being samarium, discovered just a year earlier, and which was also named after a mineral that had been named after a geologist.

Gadolinium has several properties that are key to its unique applications. It is probably best known for its magnetic properties. Gadolinium is ferromagnetic below 20 degrees Celsius and paramagnetic above this temperature. Due to these properties, gadolinium compounds are used to enhance contrast between normal and healthy tissue during magnetic resonance imaging (MRI) scanning. Gadolinium containing garnets have useful properties which lend them to applications in magneto-optical computer memory devices, however these types of computer memory have been replaced for most applications with alternative technologies that are faster and cheaper. Thin films of the magneto-optical material gadolinium-terbium-iron may also be use for these types of memory devices. Gadolinium also exhibits the magnetocaloric effect, meaning it experiences temperature changes when entering or exiting a magnetic field. This property is exploited gadolinium compounds used in magnetic refrigeration devices. Currently these devices are used primarily in research and industrial settings for ultra low temperature applications, however research developments may eventually make magnetic refrigeration a viable replacement for current commercial refrigeration technology.

An additional notable property of gadolinium is its high adsorption rate of neutrons. In nuclear energy applications, gadolinium is used in radiation shielding and in varying capacities to control the rate of the nuclear reaction. Gadolinium may also be used in neutron radiography, an imaging technology that uses neutrons much in the way x-rays are used in x-ray imaging. This technology is often used in industry for quality control when making precision parts. Gadolinium screens are used in neutron imaging to convert the neutrons that successfully pass through the imaged object into high-energy electrons which can then produce an image on x-ray film.

Gadolinium can also be used to produce compounds which exhibit luminescence either in response to the absorption of visible or near-visible light--these compounds are typically called phosphors--or in response to the absorption of ionizing radiation--these compounds are most often called scintillators. Gadolinium phosphors are used for green light in color display screens. Scintillator compounds containing gadolinium are used in sensors that detect X-rays or neutrons. These sensors are essential for the operation of medical imaging devices such as computed tomography scanners.

Gadolinium-153 is a radioactive isotope that is used in testing and calibration of medical imaging devices, bone density measurements, and in Lixiscope portable x-ray systems. Additionally, it has been investigated for potential use in radiotherapy for cancer.

In a few contexts, gadolinium is used in small quantities to alter the properties of a host material. In metallic alloys, gadolinium is used to to improve the workability of the material and increase resistance to high temperatures and oxidation. Gadolinium-doped garnets can be used in magneto-optical applications as previously mentioned, or may be used in microwave optical communications devices, lasers, or as imitation gemstones. Finally, gadolinium-doped ceria is an important potential electrolyte material for fuel cells, especially as it has higher ion conductivity and lower operating temperatures than the more commonly used yttria stabilized zirconia.

Several gadolinium compounds have been investigated for use as superconductors. Other uses currently in development for gadolinium include luminescent oxygen and temperature sensing compounds, novel high-k dielectrics for semiconductor devices, high temperature piezoelectric compounds for pressure and force detecting sensors, and compounds which can be used to immobilize and thus contain radioactive waste.

Gadolinium is a rare earth element that can be found in varying quantities in most rare-earth containing minerals. It is most commonly extracted from monazite and bastnasite.

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Gadolinium is utilized for both its high magnetic moment (7.94µB) and in phosphors and scintillator material. When complexed with EDTA ligands, it is used as an High Purity (99.999%) Gadolinium (Gd) Sputtering Targetinjectable contrast agent for patients undergoing magnetic resonance imaging. With its high magnetic moment, gadolinium can reduce High Purity (99.999%) Gadolinium Oxide (Gd2O3) Powderrelaxation times and thereby enhance signal intensity. The extra stable half-full 4f electron shell with no low lying energy levels creates applications as an inert phosphor host. Gadolinium can therefore act as hosts for x-ray cassettes and in scintillator materials for computer tomography. Gadolinium is available as metal and compounds with purities from 99% to 99.999% (ACS grade to ultra-high purity). Elemental or metallic forms include pellets, rod, wire and granules for evaporation source material purposes. Oxides are available in powder and dense pellet form for such uses as optical coating and thin film applications. Oxides tend to be insoluble. Fluorides are another insoluble form for uses in which oxygen is undesirable such as metallurgy, chemical and physical vapor deposition and in some optical coatings. Gadolinium is also available in soluble forms including chlorides, nitrates and acetates. These compounds can be manufactured as solutions at specified stoichiometries.

Gadolinium Properties

Elemental GadoliniumGadolinium is a Block F, Group 3, Period 6 element. Gadolinium Bohr ModelThe number of electrons in each of Gadolinium’s shells is 2, 8, 18, 25, 9, 2 and its electron configuration is [Xe] 4f7 5d1 6s2. The gadolinium atom has a radius of and its Van der Waals radius is In its elemental form, CAS 7440-54-2, gadolinium has a silvery-white appearance. Gadolinium was discovered by Jean Charles Galissard de Marignac in 1880 and first isolated by Lecoq de Boisbaudran in 1886. The element is named after the Finnish chemist and geologist Johan Gadolin.

Symbol: Gd
Atomic Number: 64
Atomic Weight: 157.25
Element Category: Lanthanide
Group, Period, Block: n/a, 6, f
Color: silvery-white
Other Names: Gadolinio, Gadolíneo
Melting Point: 1313°C, 2395.4°F, 1586.15 K
Boiling Point: 3273 °C, 5923.4 °F, 3546.15 K
Density: 7901 kg·m3
Liquid Density @ Melting Point: 7.4 g·cm3
Density @ 20°C: 7.895 g/cm3
Density of Solid: 7901 kg·m3
Specific Heat: 0.055 Cal/g/K @ 25°C
Superconductivity Temperature: 1.083 [or -272.067 °C (-457.72 °F)] K
Triple Point: N/A
Critical Point: N/A
Heat of Fusion (kJ·mol-1): 15.5
Heat of Vaporization (kJ·mol-1): 301
Heat of Atomization (kJ·mol-1): 398.94
Thermal Conductivity: 0.105 W/cm/K @ 298.2 K
Thermal Expansion: (100 °C, poly) 9.4 µm/(m·K)
Electrical Resistivity: 140.5 µΩ-cm @ 25°C
Tensile Strength: N/A
Molar Heat Capacity: 37.03 J·mol-1·K-1
Young's Modulus: (? form) 54.8 GPa
Shear Modulus: (? form) 21.8 GPa
Bulk Modulus: (? form) 37.9 GPa
Poisson Ratio: (? form) 0.259
Mohs Hardness: N/A
Vickers Hardness: 570 MPa
Brinell Hardness: N/A
Speed of Sound: (20 °C) 2680 m·s-1
Pauling Electronegativity: 1.2
Sanderson Electronegativity: N/A
Allred Rochow Electronegativity: 1.11
Mulliken-Jaffe Electronegativity: N/A
Allen Electronegativity: N/A
Pauling Electropositivity: 2.8
Reflectivity (%): N/A
Refractive Index: N/A
Electrons: 64
Protons: 64
Neutrons: 93
Electron Configuration: [Xe] 4f7 5d1 6s2
Atomic Radius: 180 pm
Atomic Radius,
non-bonded (Å):
Covalent Radius: 196±6 pm
Covalent Radius (Å): 1.82
Van der Waals Radius: 237 pm
Oxidation States: 1, 2, 3 (mildly basic oxide)
Phase: Solid
Crystal Structure: hexagonal close-packed
Magnetic Ordering: ferromagnetic/paramagnetic
Electron Affinity (kJ·mol-1) Unknown
1st Ionization Energy: 593.40 kJ·mol-1
2nd Ionization Energy: 1166.52 kJ·mol-1
3rd Ionization Energy: 1990.51 kJ·mol-1
CAS Number: 7440-54-2
EC Number: 231-162-2
MDL Number: MFCD00011022
Beilstein Number: N/A
SMILES Identifier: [Gd]
InChI Identifier: InChI=1S/Gd
PubChem CID: 23982
ChemSpider ID: 22418
Earth - Total: 286 ppb
Mercury - Total: 220 ppb
Venus - Total: 300 ppb
Earth - Seawater (Oceans), ppb by weight: 0.0007
Earth - Seawater (Oceans), ppb by atoms: 0.000028
Earth -  Crust (Crustal Rocks), ppb by weight: 5200
Earth -  Crust (Crustal Rocks), ppb by atoms: 680
Sun - Total, ppb by weight: 2
Sun - Total, ppb by atoms: 0.01
Stream, ppb by weight: 0.04
Stream, ppb by atoms: 0.0003
Meterorite (Carbonaceous), ppb by weight: 230
Meterorite (Carbonaceous), ppb by atoms: 30
Typical Human Body, ppb by weight: N/A
Typical Human Body, ppb by atom: N/A
Universe, ppb by weight: 2
Universe, ppb by atom: 0.02
Discovered By: Jean Charles Galissard de Marignac
Discovery Date: 1880
First Isolation: Lecoq de Boisbaudran (1886)

Health, Safety & Transportation Information for Gadolinium

Gadolinium can be very toxic. Safety data for Gadolinium and its compounds can vary widely depending on the form. For potential hazard information, toxicity, and road, sea and air transportation limitations, such as DOT Hazard Class, DOT Number, EU Number, NFPA Health rating and RTECS Class, please see the specific material or compound referenced in the Products tab. The following applies to elemental (metallic) Gadolinium.

Safety Data
Material Safety Data Sheet MSDS
Signal Word Warning
Hazard Statements H261
Hazard Codes F
Risk Codes 15
Safety Precautions 43
RTECS Number N/A
Transport Information UN 3208 4.3 / PGIII
WGK Germany 3
Globally Harmonized System of
Classification and Labelling (GHS)

Gadolinium Isotopes

Gadolinium (Gd) has 6 stable isotopes: 154Gd, 155Gd, 156Gd, 157Gd, 158Gd and 160Gd.

Nuclide Isotopic Mass Half-Life Mode of Decay Nuclear Spin Magnetic Moment Binding Energy (MeV) Natural Abundance
(% by atom)
134Gd 133.95537(43)# 0.4# s Unknown 0+ N/A 1057.32 -
135Gd 134.95257(54)# 1.1(2) s Unknown 3/2- N/A 1065.4 -
136Gd 135.94734(43)# 1# s [>200 ns] ß+ to 136Eu N/A N/A 1082.79 -
137Gd 136.94502(43)# 2.2(2) s ß+ to 137Eu 7/2+# N/A 1090.87 -
138Gd 137.94012(21)# 4.7(9) s ß+ to 138Eu 0+ N/A 1098.95 -
139Gd 138.93824(21)# 5.7(3) s ß+ to 139Eu 9/2-# N/A 1116.34 -
140Gd 139.93367(3) 15.8(4) s ß+ to 140Eu 0+ N/A 1124.42 -
141Gd 140.932126(21) 14(4) s ß+ to 141Eu; ß+ + p to 140Sm (1/2+) N/A 1132.5 -
142Gd 141.92812(3) 70.2(6) s ß+ to 142Eu 0+ N/A 1149.89 -
143Gd 142.92675(22) 39(2) s ß+ to 143Eu (1/2)+ N/A 1157.97 -
144Gd 143.92296(3) 4.47(6) min ß+ to 144Eu 0+ N/A 1166.05 -
145Gd 144.921709(20) 23.0(4) min ß+ to 145Eu 1/2+ N/A 1174.13 -
146Gd 145.918311(5) 48.27(10) d EC to 146Eu 0+ N/A 1191.53 -
147Gd 146.919094(3) 38.06(12) h EC to 147Eu 7/2- 1 1199.6 -
148Gd 147.918115(3) 74.6(30) y a to 144Sm 0+ N/A 1207.68 -
149Gd 148.919341(4) 9.28(10) d EC to 149Eu; a to 145Sm 7/2- 0.9 1215.76 -
150Gd 149.918659(7) 1.79(8)E+6 y a to 146Sm 0+ N/A 1223.84 -
151Gd 150.920348(4) 124(1) d EC to 151Eu; a to 147Sm 7/2- 0.8 1222.6 -
152Gd 151.9197910(27) 1.08(8)E+14 y a to 148Sm 0+ N/A 1240 0.2
153Gd 152.9217495(27) 240.4(10) d EC to 153Eu 3/2- 0.4 1238.76 -
154Gd 153.9208656(27) Observationally Stable - 0+ N/A 1246.84 2.18
155Gd 154.9226220(27) Observationally Stable - 3/2- -0.2591 1254.92 14.8
156Gd 155.9221227(27) STABLE - 0+ N/A 1263 20.47
157Gd 156.9239601(27) STABLE - 3/2- -0.3399 1271.08 15.65
158Gd 157.9241039(27) STABLE - 0+ N/A 1279.15 24.84
159Gd 158.9263887(27) 18.479(4) h ß- to 159Tb 3/2- -0.44 1287.23 -
160Gd 159.9270541(27) Observationally Stable - 0+ N/A 1295.31 21.86
161Gd 160.9296692(29) 3.646(3) min ß- to 161Tb 5/2- N/A 1303.39 -
162Gd 161.930985(5) 8.4(2) min ß- to 162Tb 0+ 2 1302.15 -
163Gd 162.93399(32)# 68(3) s ß- to 163Tb 7/2+# N/A 1310.23 -
164Gd 163.93586(43)# 45(3) s ß- to 164Tb 0+ 1.9 1318.31 -
165Gd 164.93938(54)# 10.3(16) s ß- to 165Tb 1/2-# N/A 1326.39 -
166Gd 165.94160(64)# 4.8(10) s ß- to 166Tb 0+ 1.8 1325.15 -
167Gd 166.94557(64)# 3# s ß- to 167Tb 5/2-# N/A 1333.23 -
168Gd 167.94836(75)# 300# ms ß- to 168Tb 0+ 1.4 1341.31 -
169Gd 168.95287(86)# 1# s ß- to 169Tb 7/2-# N/A 1340.07 -