Overview of a Rare Earth Element - Gadolinium
Basic information
Represented as Gd with atomic number 64,
gadolinium is a rare-earth metal utilized in critical applications such as
magnetic resonance imaging and jewelry making. In 1880, Jean Charles Galissard
de Marignac first discovered this element. Subsequently, in 1886, French
chemist Paul-Emile Lecoq de Boisbaudran became the first to isolate pure
gadolinium metal. Notably, gadolinium is named after Finnish scientist Johan
Gadolin, despite his lack of direct involvement in its discovery. Today,
gadolinium's unique magnetic properties drive its use in MRI contrast agents.
Additionally, its malleability and ductility allow it to create specialized
alloys, like the gadolinium-cobalt used in Samarium-cobalt magnets.
Furthermore, gadolinium generates a brilliant white color when alloyed with
other metals, making it useful for creating costume jewelry pieces. Overall,
gadolinium’s distinct magnetic and metallurgical qualities have made it
essential for various advanced technologies and materials since its isolation
over a century ago.
Due to its high reactivity, gadolinium rarely occurs naturally in its pure elemental form. Instead, it exists within other mineral compounds like monazite, gadolinite, and bastnasite. Annually, producers generate around 400 tons of gadolinium worldwide, extracting it from sources primarily in Brazil, China, the United States, Sri Lanka, and Australia. During separation, gadolinium's compounds dissolve easily in acids, distinguishing it from other rare earths. Furthermore, electrolysis or metal reduction processes can isolate the pure metal. Moreover, gadolinium's malleability facilitates purification and fabrication once extracted. Overall, gadolinium's distinct chemical properties allow efficient extraction from minerals and reactivity with acids, enabling approximately 400 tons of the exceptionally useful metal to be isolated globally each year.
Gadolinium possesses six naturally occurring isotopes, with mass numbers of 154, 155, 156, 157, 158, and 160. Additionally, gadolinium has one radioactive isotope, 152Gd. Of these isotopes, 158Gd appears most abundantly in nature, while 152Gd occurs least often and must be produced artificially. The different gadolinium isotopes find uses based on their varied nuclear properties. For example, 155Gd and 157Gd have high thermal neutron capture cross-sections, enabling applications in neutron capture therapy. Overall, gadolinium isotopes display a range of abundances and nuclear traits, permitting specialized uses in medicine, industry, and science.
Properties
In period 6 and the f-block of the periodic table resides the rare-earth element gadolinium. Its defined position grants gadolinium distinct physical and chemical qualities. Specifically, with 2 valence electrons and a standard atomic weight of 157.25, gadolinium adopts a lustrous, silvery appearance and hexagonal close-packed crystal lattice. Under standard conditions, gadolinium remains a solid metal, with a high melting point of 1585 K that allows fabrication into alloys and compounds. Additionally, gadolinium evaporates at an elevated boiling point of 3273 K. Furthermore, gadolinium frequently takes the +3 oxidation state in chemical compounds, as do most other lanthanide rare earths. This stable 3+ charge underlies gadolinium's vivid luminescence and paramagnetism. However, the element also forms versatile compounds in the +2 state when appropriate conditions allow. Overall, gadolinium's attributes stem from its defined position on the periodic table, granting this malleable rare earth unique magnetic, optical, and chemical reactivities crucial for specialized applications ranging from magnets to lasers.
Gadolinium displays unique interactions with magnetic fields. When exposed to a magnetic field, gadolinium heats up as the spins of its electrons align with the external field. However, its temperature drops once the field disappears and random spin orientations reemerge. Furthermore, gadolinium exhibits both ferromagnetic and paramagnetic states. Below 293 K, gadolinium acts as a permanent magnet due to strong spin alignments. But above this threshold, thermal energy overcomes the alignments, inducing paramagnetism. Moreover, gadolinium demonstrates high malleability and ductility. This grants gadolinium the ability to be drawn into wires or pressed into sheets. Additionally, gadolinium experiences density changes between solid and liquid forms. At 7.90 g/cm3in the solid state, its density decreases to 7.4 g/cm3upon melting. Overall, gadolinium displays versatile magnetism, efficient conductivity, and advanced metallurgical properties that lend well to numerous technological uses.
When exposed to moist air, gadolinium actively oxidizes to form a black coating. Additionally, it readily reacts with dilute sulfuric acid and the halogens fluorine, chlorine, and iodine to form the corresponding chemicals, such as GdF3. Gadolinium also combines with water, producing gadolinium hydroxide. Due to its high reactivity, gadolinium does not often appear naturally in its pure form. However, its not that reactive so Gd is still able to expose to air in short term, and still remain silvery apperance. As a result, there are certian Gd products as metal shape and other compounds.
Like other rare-earths, gadolinium's traits stem from its location on the periodic table, granting it comparable properties. However, gadolinium possesses unique qualities that enable key applications. Specifically, gadolinium's paramagnetism facilitates its use in MRI contrast agents, taking advantage of its interactions with magnetic fields. Additionally, gadolinium's malleability allows it to alloy with metals, producing materials for electronics, magnets, and metalworking. Furthermore, gadolinium compounds display fluorescent and phosphorescent properties, permitting uses in lighting, lasers, and imaging. Overall, gadolinium's distinctive combination of chemical, magnetic, and metallurgical attributes facilitate its essential roles across medicine, technology, and science.
Applications
MRI contrast agents- Gadolinium compounds like gadopentetate dimeglumine are used to enhance contrast in magnetic resonance imaging scans. Gadolinium's paramagnetism alters proton relaxation rates in tissues.
Phosphors- Gadolinium phosphors emit useful fluorescent and phosphorescent light when exposed to radiation or electricity. This allows uses in CRT displays, computer memory, and X-ray imaging.
Magnets- Gadolinium alloys with cobalt and iron help create extremely powerful rare earth magnets used in motors, generators, and computer hard drives.
Data storage- The magneto-optic properties of gadolinium enable applications in rewritable optical data storage like CDs and DVDs.
Lasers- Certain solid-state laser crystals incorporate gadolinium as an activator ion to produce specific wavelengths.
Neutron detection- Gadolinium's very high thermal neutron absorption makes it useful for neutron detection in nuclear power and scientific applications.
In summary, gadolinium finds roles in medicine, industry, technology, and research based on its specialized magnetic, optical, and metallurgical properties. It is an essential component of MRI and lasers in particular. Some of the applications involves thinfilm coatings. In this case, Gd is usually consumed in sputtering process (a PVD technique) as the target material. QSAM INC is a prominent supplier of rare earth metal products in the United States, offering a diverse range of materials such as targets, strips, foils, and wires. Our product catalog includes rare earth metals like gadolinium, tailored to support scientific research and high-end industrial clients. We are dedicated to fostering advancements at the cutting edge of technology.
A 2" dia. Gd sputter target
Conclusion
Though rare, gadolinium serves as a vital element across numerous industries. Its low crustal abundance does not prevent gadolinium from enabling impactful applications. In particular, gadolinium's unparalleled utility in MRI scanning makes it essential for modern medicine. Additionally, gadolinium compounds produce the phosphors and laser crystals that power electronic displays and optical technologies. Furthermore, gadolinium alloys contribute to the super-strength magnets that allow miniaturized devices. Therefore, despite its scarcity, gadolinium's singular properties render it irreplaceable for various advanced technologies and materials.