Gadolinium

Gadolinium is a chemical element that has the symbol Gd and atomic number 64. Gadolinium is a silvery-white, malleable and ductile rare-earth metal with a metallic luster. It 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 and forms a loosely-adhering oxide that spalls off, and then exposes more surface to oxidation. Gadolinium reacts slowly with water, and it is soluble in dilute acids.
General | |||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Name, Symbol, Number | gadolinium, Gd, 64 | ||||||||||||||
Chemical series | lanthanides | ||||||||||||||
Group, Period, Block | n/a, 6, f | ||||||||||||||
Appearance | silvery white |
||||||||||||||
Standard atomic weight | 157.25(3) g·mol-1 | ||||||||||||||
Electrons per shell | 2, 8, 18, 25, 9, 2 | ||||||||||||||
Physical properties | |||||||||||||||
Phase | solid | ||||||||||||||
Density (near r.t.) | 7.90 g·cm−3 | ||||||||||||||
Liquid density at m.p. | 7.4 g·cm−3 | ||||||||||||||
Melting point | 1585K (1312°C, 2394°F) |
||||||||||||||
Boiling point | 3546K (3273°C, 5923°F) |
||||||||||||||
Heat of fusion | 10.05 kJ·mol-1 | ||||||||||||||
Heat of vaporization | 301.3 kJ·mol-1 | ||||||||||||||
Heat capacity | (25°C) 37.03 J·mol-1·K-1 | ||||||||||||||
|
|||||||||||||||
Atomic properties | |||||||||||||||
Crystal structure | hexagonal | ||||||||||||||
Oxidation states | 3 (mildly basic oxide) |
||||||||||||||
Electronegativity | 1.20 (Pauling scale) | ||||||||||||||
Ionization energies (more) |
1st: 593.4 kJ·mol-1 | ||||||||||||||
2nd: 1170 kJ·mol-1 | |||||||||||||||
3rd: 1990 kJ·mol-1 | |||||||||||||||
Atomic radius | 180 pm | ||||||||||||||
Atomic radius (calc.) | 233 pm | ||||||||||||||
Miscellaneous | |||||||||||||||
Magnetic ordering | ferromagnetic | ||||||||||||||
Electrical resistivity | (r.t.) (α, poly) 1.310 µΩ·m |
||||||||||||||
Thermal conductivity | (300K) 10.6 W·m-1·K-1 | ||||||||||||||
Thermal expansion | (100 °C) (α, poly) 9.4 µm/(m·K) |
||||||||||||||
Speed of sound (thin rod) | (20 °C) 2680 m/s | ||||||||||||||
Young's modulus | (α form) 54.8 GPa | ||||||||||||||
Shear modulus | (α form) 21.8 GPa | ||||||||||||||
Bulk modulus | (α form) 37.9 GPa | ||||||||||||||
Poisson ratio | (α form) 0.259 | ||||||||||||||
Vickers hardness | 570 MPa | ||||||||||||||
CAS registry number | 7440-54-2 |

Content from Wikipedia for educational use and displayed with permission under the GFDL.
Please report any inaccuracies to the Webmaster.