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Chemistry of Scandium

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  • This module was designed to give general information about Scandium, a transition metal element. Having some knowledge of the properties of Scandium provides for a better understanding of the production of items such as spacecraft and sports equipment, as well as providing for a better general understanding of Earth's elements.


    Scandium was one of the elements predicted by Mendeleev in 1871 when he proposed his system for organizing the elements: the periodic table. At the time he called it ekaboron ("like boron") and suggested some of the physical and chemical properties it would have. The existence of scandium was confirmed only 8 years later by Lars Nilson. It is named for the Latin word for Scandinavia.

    The metal is lightweight and fairly corrosion-resistant. It also has a high melting point and therefore finds applications in the aerospace industry. Scandium is widely distributed on the earth and has an abundance similar to cobalt and lithium. Most commercial scandium is obtained from the uranium refining process.

    Properties of Scandium

    General Properties of Scandium

    • Atomic Number: 21
    • Mass: 44.955912 g
    • Density: 2.985 g/ml
    • Melting Point: 1814 K
    • Boiling Point: 3109 K
    • Electronegativity: 1.36
    • Specific heat: 0.568 J / mol K
    • Atomic Radius: 160
    • Covalent Radius: 144
    • ∆H Fusion: 14.1 kJ / mol
    • ∆H Vaporization: 332.7 kJ / mol
    • Electron Configuration: [Ar] 4s2 3d1
    • Common Ions: 3+ (most common), 2+, 1+
    • Crystal Structure: Hexagonal

    Metallic Properties of Scandium

    Scandium is a silver-white metal that develops a light yellow/pink cast when exposed to air. Scandium has a much higher melting point than aluminum, which is why it is of interest to spacecraft designers. Like other transition metals, it is susceptible to weathering and will slowly dissolve in dilute acids.


    Isotopes of Scandium

    Isotope Half Life
    Sc-44 3.92 hours
    Sc-45 Stable
    Sc-46 83.81 days
    Sc-46m 18.72 seconds
    Sc-47 3.34 days
    Sc-48 43.67 hours

    57.3 minutes

    Common Compounds

    • Scandium Dihydride ScH2
    • Scandium Trihidride ScH3
    • Scandium Trifluoride ScF3
    • Scandium Trichloride ScCl3
    • Scandium Triiodide ScI3
    • Discandium Trioxide Sc2O3
    • Discandium Trisulphide Sc2S3
    • Discandium Tritelluride Sc2Te3

    As seen above, many of these examples substantiate the fact that Scandium's most common oxidation state is +3, with the +2 and +1 oxidation states being rarer but nonetheless possible.

    Applications of Scandium

    The main use of Scandium is in the making of aluminum-scandium alloys for aerospace industry components. However, only 0.1% - 0.5% of Scandium is used for this application. Another use of Scandium is in aluminum-scandium alloys for sports equipment, such as bicycle frames, lacrosse sticks, and baseball bats. This is done because the aluminum-scandium alloy allows for high athletic performance. Another application used often in the United States is in Scandium Oxide (Sc2O3) to make high intensity discharge lamps.

    Comparison with Other Transition Metals

    Scandium works well with Aluminum, as can be seen when they're used together in sports equipment and aerospace components. Scandium has the lowest atomic mass out of the all of the transition metals, as well as the lowest density.


    1. Petrucci et al. General Chemistry: Principles & Modern Applications, 9th Edition. New Jersey: Pearson Education, Inc., 2007.
    2. Eagleson, M. (1994). Concise encyclopedia chemistry, Walter De Gruyter Inc.
    3. Ahmad, Zaki (2003). "The properties and application of scandium-reinforced aluminum". JOM 55: 35.

    Practice Problems

    1. In \(Sc_2O_3\), what is the oxidation state of Sc and what is its electron configuration? 3+
    2. How many protons are in Scandium? 21
    3. Why does scandium have no +4 oxidation state in any of its compounds?
    4. Is scandium radioactive?
    5. Where is Scandium found?


    1. 3+
    2. 21
    3. Scandium is in column 3, 3 outside electrons to be removed (It loses 1 in 4s and 2 in 3d)
    4. There are no radioactive istopes of scandium ordinarily found in nature. Like all elements, synthetic radioactive isotopes of scandium exist.
    5. It is found in thortveitite and in small amounts, in other minerals.


    • Kevin Fan (UCD)
    • Katherine Cubbon