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Element 69 - Thulium (Tm) sound

From Thule, or Northland; discovered 1879. When irradiated in a nuclear reactor, thulium produces an isotope that gives off X-rays. A "button" of this isotope is used to make a lightweight, portable X-ray machine for medical use. The "hot" thulium is replaced every few months.

Properties

Atomic Number: 69
Atomic Weight: 168.9342
Electron Configuration (at ground state): 1s22s22p63s23p63d104s24p64d104f135s25p66s2
Oxidation States (Bold most stable): +3, +2
Boiling Point (K): 2223
Melting Point (K): 1818
Density (at 300K -- g/cm3): 9.32
Atomic Volume (at 300K -- cm3/mol) 18.1
Number of stable isotopes: 1
Mass Number (Bold naturally occurring) -- Half-Life -- Disintigration Type: 170 -- 128.6 days -- beta particle (electron) emission
171 -- 1.92 years -- beta particle (electron) emission
Covalent Radius (Å): 1.56
Atomic Radius (Å): 1.77
First Ionization Potential (V): 6.184
Electronegativity (Pauling's): 1.25
Specific Heat Capacity (at 300K -- J g-1 K-1): 0.16
Heat of Vaporization (kJ/mol): 191
Heat of Fusion (kJ/mol): 16.8
Electrical Conductivity (at 293K for polycrystalline material -- 106 (ohms)-1 cm-1): 1.3
Thermal Conductivity (at 300K -- W m-1 K-1): 16.8
Crystal Structure: Hexagonal
Acid-Base Properties: Slightly basic