Scandium is a chemical element. Scandium is the knowledge you don't know
Scandium is a chemical element with the element symbol Sc and atomic number 21. It is a soft, silvery transition metal with a melting point of 1541 ℃ and a boiling point of 2831 ℃. It is soluble in water and can react with hot water. It is easy to darken in the air. Its main valence is+3. It is often mixed with gadolinium and erbium, and its output is very small, and its content in the crust is about 0.0005%. Scandium is often used to make special glass and light heat-resistant alloy.
Scandium is slightly yellow or pink when oxidized by air, and is easily weathered and slowly dissolved in most dilute acids. However, an impermeable passivation layer is easily formed on the surface in strong acid, so it does not react with the 1:1 mixture of nitric acid (HNO3) and hydrofluoric acid (HF).
Scandium earth Sc2O3, with a specific gravity of 3.86, is more alkaline than alumina, weaker than yttrium oxide and magnesium oxide, and does not react with ammonium chloride.
The salts are colorless and form colloidal precipitation with potassium hydroxide and sodium carbonate. It is difficult for various salts to crystallize well. Scandium salt is colorless, forms colloidal precipitation with potassium hydroxide and sodium carbonate, and sulfate is extremely difficult to crystallize.
Carbonate is insoluble in water and may form alkaline carbonate precipitation. Scandium carbonate is insoluble in water and can easily remove carbon dioxide. Sulfuric acid double salt may not form alum. The complex salt of scandium sulfate does not form alum.
The volatility of anhydrous chloride ScCl3 is lower than that of aluminum chloride, and it is easier to hydrolyze than magnesium chloride. The sublimation temperature of ScCl3 is 850 ℃, while that of AlCl3 is 100 ℃, which is hydrolyzed in aqueous solution.
