Gadolinium

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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
Vapor pressure (calculated)
P(Pa) 1 10 100 1 k 10 k 100 k
at T(K) 1836 2028 2267 2573 2976 3535
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

 

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