Scandium is a chemical element with the symbol Sc and atomic number 21. It is a silvery-white metallic d-block element. Historically, it has been classified as a rare-earth element, together with yttrium and the Lanthanides. It was discovered in 1879 by spectral analysis of the minerals euxenite and gadolinite from Scandinavia.
Group 3 is the first group of transition metals in the periodic table. This group is closely related to the rare-earth elements. It contains the four elements scandium (Sc), yttrium (Y), lutetium (Lu), and lawrencium (Lr). The group is also called the scandium group or scandium family after its lightest member.
Naturally occurring scandium (21Sc) is composed of one stable isotope, 45Sc. Twenty-five radioisotopes have been characterized, with the most stable being 46Sc with a half-life of 83.8 days, 47Sc with a half-life of 3.35 days, and 48Sc with a half-life of 43.7 hours and 44Sc with a half-life of 3.97 hours. All the remaining isotopes have half-lives that are less than four hours, and the majority of these have half-lives that are less than two minutes, the least stable being proton unbound 39Sc with a half-life shorter than 300 nanoseconds. This element also has 13 meta states with the most stable being 44m2Sc.
Scandium(III) oxide or scandia is a inorganic compound with formula Sc2O3. It is one of several oxides of rare earth elements with a high melting point. It is used in the preparation of other scandium compounds as well as in high-temperature systems (for its resistance to heat and thermal shock), electronic ceramics, and glass composition (as a helper material).
Scandium(III) chloride is the inorganic compound with the formula ScCl3. It is a white, high-melting ionic compound, which is deliquescent and highly water-soluble. This salt is mainly of interest in the research laboratory. Both the anhydrous form and hexahydrate (ScCl3•6H2O) are commercially available.
Scandium(III) fluoride, ScF3, is an ionic compound. This salt is slightly soluble in water but dissolves in the presence of excess fluoride to form the ScF63− anion.
Scandium(III) sulfide is a chemical compound of scandium and sulfur with the chemical formula Sc2S3. It is a yellow solid.
An aluminium alloy is an alloy in which aluminium (Al) is the predominant metal. The typical alloying elements are copper, magnesium, manganese, silicon, tin, nickel and zinc. There are two principal classifications, namely casting alloys and wrought alloys, both of which are further subdivided into the categories heat-treatable and non-heat-treatable. About 85% of aluminium is used for wrought products, for example rolled plate, foils and extrusions. Cast aluminium alloys yield cost-effective products due to the low melting point, although they generally have lower tensile strengths than wrought alloys. The most important cast aluminium alloy system is Al–Si, where the high levels of silicon (4–13%) contribute to give good casting characteristics. Aluminium alloys are widely used in engineering structures and components where light weight or corrosion resistance is required.
Lead scandium tantalate (PST) is a mixed oxide of lead, scandium, and tantalum. It has the formula Pb(Sc0.5Ta0.5)O3. It is a ceramic material with a perovskite structure, where the Sc and Ta atoms at the B site have an arrangement that is intermediate between ordered and disordered configurations, and can be fine-tuned with thermal treatment. It is ferroelectric at temperatures below 270 K (−3 °C; 26 °F), and is also piezoelectric. Like structurally similar lead zirconate titanate and barium strontium titanate, PST can be used for manufacture of uncooled focal plane array infrared imaging sensors for thermal cameras.
Scandium-44 (44Sc) is a radioactive isotope of scandium that decays by positron emission to stable 44Ca with a half-life of 4.042 hours.
Organoscandium chemistry is an area with organometallic compounds focused on compounds with at least on carbon to scandium chemical bond. The interest in organoscandium compounds is mostly academic but motivated by potential practical applications in catalysis, especially in polymerization. A common precursor is scandium chloride, especially its THF complex.
Scandium compounds are compounds containing the element scandium. The chemistry of scandium is almost completely dominated by the trivalent ion, Sc3+, due to its electron configuration, [Ar] 3d14s2. The radii of M3+ ions in the table below indicate that the chemical properties of scandium ions have more in common with yttrium ions than with aluminium ions. In part because of this similarity, scandium is often classified as a lanthanide-like element.
Scandium triiodide, also known as scandium iodide, is an inorganic compound with the formula ScI3 and is classified as a lanthanide iodide. This salt is a yellowish powder. It is used in metal halide lamps together with similar compounds, such as caesium iodide, because of their ability to maximize emission of UV and to prolong bulb life. The maximized UV emission can be tuned to a range that can initiate photopolymerizations.
Scandiobabingtonite was first discovered in the Montecatini granite quarry near Baveno, Italy in a pegmatite cavity. Though found in pegmatites, the crystals of scandiobabingtonite are sub-millimeter sized, and are tabular shaped. Scandiobabingtonite was the sixth naturally occurring mineral discovered with the rare earth element scandium, and grows around babingtonite, with which it is isostructural, hence the namesake. It is also referred to as scandian babingtonite. The ideal chemical formula for scandiobabingtonite is Ca2(Fe2+,Mn)ScSi5O14(OH).
Scandium nitride (ScN) is a binary III-V indirect bandgap semiconductor. It is composed of the scandium cation and the nitride anion. It forms crystals that can be grown on tungsten foil through sublimation and recondensation. It has a rock-salt crystal structure with lattice constant of 0.451 nanometer, an indirect bandgap of 0.9 eV and direct bandgap of 2 to 2.4 eV. These crystals can be synthesized by dissolving nitrogen gas with indium-scandium melts, magnetron sputtering, MBE, HVPE and other deposition methods. Scandium Nitride is also an effective gate for semiconductors on a silicon dioxide (SiO2) or hafnium dioxide (HfO2) substrate.
Scandium(III) hydroxide is an inorganic compound with the chemical formula Sc(OH)3, the trivalent hydroxide of scandium. It is an amphoteric compound. It is slightly soluble in water, and its saturated solution (pH = 7.85) contains Sc(OH)3 and a small amount of Sc(OH)2+. The solubility of scandium(III) hydroxide in water is 0.0279 mol/L. It will convert to ScO(OH) after aging, greatly reducing the solubility (0.0008 mol/L). Scandium(III) hydroxide can be produced by reacting scandium salts and alkali hydroxides. In the reaction, different starting ingredients can generate different intermediates such as Sc(OH)1.75Cl1.25, Sc(OH)2NO3 and Sc(OH)2.32(SO4)0.34.
Scandium phosphide is an inorganic compound of scandium and phosphorus with the chemical formula ScP.
Neodymium acetate is an inorganic salt composed of a neodymium atom trication and three acetate groups as anions where neodymium exhibits the +3 oxidation state. It has a chemical formula of Nd(CH3COO)3 although it can be informally referred to as NdAc because Ac is an informal symbol for acetate. It commonly occurs as a light purple powder.
Europium(III) acetate is an inorganic salt of europium and acetic acid with the chemical formula of Eu(CH3COO)3. In this compound, europium exhibits the +3 oxidation state. It can exist in the anhydrous form, sesquihydrate and tetrahydrate. Its hydrate molecule is a dimer.
Erbium compounds are compounds containing the element erbium (Er). These compounds are usually dominated by erbium in the +3 oxidation state, although the +2, +1 and 0 oxidation states have also been reported.
