Gadolinium, Gd

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.

Gadolinium-157 has the highest thermal neutron capture cross-section of any known nuclide with the exception of Xenon-135, 49,000 barns, but it also has a fast burn-out rate, limiting its usefulness as a nuclear control rod material.

Gadolinium becomes superconductive below a critical temperature of 1.083 K. It is strongly paramagnetic at room temperature, and exhibits ferromagnetic properties below room temperature.

Gadolinium demonstrates a magnetocaloric effect whereby its temperature increases when it enters a magnetic field and decreases when it leaves the magnetic field. The effect is considerably stronger for the gadolinium alloy Gd5(Si2Ge2).

Technical Data
Symbol Gd Density (20°C)/gcm-3 7.886
Atomic number 64 Melting point /°C 1312
No. of naturally occurring isotopes 7 Boiling point /°C -3000
Atomic weight 157.25 (+/-3) ΔHvap/kJmol-1 301
Outer electron configuration 4f7d46s2 ΔHf(monoatomic gas/kJmol-1 398
Metal radius(6-coordinate)/pm 180.4 ΔH(hydration Ln3+)/kJmol-1 3571
Ionic radius(6-coordinate)/pm III 93.8 Ionization energy/kJ mol-1 I 595
Ionic radius(6-coordinate)/pm II - Ionization energy/kJmol-1 II 1172
Electrical resistivity   Ionization energy/kJmol-1 III 1999
(25°C)/μohm cm 134    
Evaporation Techniques
Temperature (oC) @Vap. Pressure Techniques Remarks
10-8 Torr 10-6 Torr 10-4 Torr Electron Beam Crucible Coil Boat
760 900 1175 Excellent Al2O3 - Tantalum High Tantalum solubility.

Evaporation Materials
G1-5000-M 1-4mm pieces
G1-5001-M Ingot (Please ask for sizes)
G1-5002-M pieces 12mm and smaller

The foils are available in either rectangular or circular shape. Please enter width and length or diameter of the required foil.

Foil
G1-3003-F 0.004" (0.1mm)
G1-3007-F 0.008" (0.2mm)
Powder
G1-10000-P -40 mesh
Rods
G1-2000-R 0.250" (6.35mm)
G1-2001-R 0.500" (12.7mm)
Sheet
G1-4002-S 0.020" (0.5mm)
G1-4003-S 0.030" (0.76mm)
G1-4004-S 0.040" (1.0mm)