Symbol: Gd
Atomic number: 64
Category: lanthanides
Group: n/a
Period: 6
Block: f
Atomic weight: 157.25 g/mol
Electrons per shell: 2, 8, 18, 25, 9, 2
CAS number: 7440-54-2
Phase: solid
Density: 7.90 kg/dm3 (near room temperature)
Melting point: 1585 K (1312 C, 2394 F)
Boiling point: 3546 K (3273 C, 5923 F)
Crystal structure: hexagonal
Oxidation states: 3
Electronegativity: 1.20 (Pauling scale)
Name's origin: Johan Gadolin
Name's meaning: the Finnish chemist and geologist
- is a silvery-white, malleable and ductile rare- earth metal with a metallic lustre
- crystallizes in hexagonal, close-packed alpha form at room temperature, but, when heated to 1508 K or more, it transforms into its beta form, which has a body-centered cubic structure
- unlike other rare earth elements, gadolinium is relatively stable in dry air - however, it tarnishes quickly in moist air, forming a loosely-adhering oxide which spalls off, exposing more surface to oxidation
- is used for making gadolinium yttrium garnets, which have microwave applications, and gadolinium compounds are used for making phosphors for colour TV tubes
- is used in nuclear marine propulsion systems as a burnable poison
- has no known native biological role, but in research on biological systems it has a few roles - it is used as a component of MRI contrast agents
- is never found in nature as the free element, but is contained in many rare minerals such as monazite and bastnasite
- occurs only in trace amounts in the mineral gadolinite, which was also named after Johan Gadolin
- as with the other lanthanides, gadolinium compounds are of low to moderate toxicity, although their toxicity has not been investigated in detail
- in patients with renal failure or other pro- inflammatory conditions, there is data associating its use with development of nephrogenic fibrosing dermopathy as a side effect of gadolinium chelates used as a contrast agent for MRI examinat