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    Tm

    Thulium

    Lanthanide

    Atomic Number: 69 • Atomic Mass: 168.9300 u • Period: 6 • Group: 101

    Electron Configuration: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁶ 6s² 4f¹³
    Phase: Solid
    Electronegativity: 1.25
    Erbium (Er)Ytterbium (Yb)
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    Occurrence

    Thulium is found in various natural sources, including minerals, rocks, and the Earth's crust.

    • Earth's crust (0.5 parts per million)
    • Monazite sand
    • Xenotime mineral