scandium

Japanese: スカンジウム

Sc. Atomic number 21. Group 3 metal element in the periodic table with electron configuration [Ar]3d ¹ 4s ^2. A member of the yttrium group of rare earth elements. Atomic weight 44.955912(6). A stable isotope with mass number 45 (100%) and radioactive isotopes with mass numbers 36 to 60 are known. It was discovered in gadolinite by LF Nilson in 1879, and was soon found to be identical to ekaboron predicted by DI Mendeleev. The element's name comes from Scandia, Latin for Scandinavia. Scandium minerals include tortveitite, Sc ₂ Si ₂ O _7. It is widely distributed in the earth's crust with an abundance of 30 ppm, but the quality of the ore is low. It is obtained as a by-product of tungsten and uranium smelting. It is the most expensive of the rare earth elements. The main producing countries are China, Kazakhstan, Russia and Ukraine. The metal is silvery white and exists in two modifications, α (hexagonal close-packed) and β (cubic close-packed, > 950 °C). Its melting point is 1541 °C and its boiling point is 2831 °C. Its density is 2.989 g cm ^-3 (20 °C). Its oxidation number is 3. Its standard electrode potential is Sc ³⁺ /Sc-2.03 V. Its first ionization energy is 6.54 eV. It has properties similar to those of aluminum, but is classified as a rare earth element. Its compounds include _{Sc 2} O ₃ , ScX ₃ , and ScOX, as well as oxo acids. _{Sc 2} O ₃ ･ n H ₂ O is an amphoteric compound. Scandium compounds are weaker in basicity than yttrium and lanthanum, and are therefore easily hydrolyzed to form polymers with OH bridges. In solution, complex ions such as ScCl ₂ ⁺ and ScCl ²⁺ also occur, and so-called double salts such as K ₂ SO ₄ ･Sc ₂ (SO ₄ ) ₃ ･ n H ₂ O also occur. Like rare earth elements, fluorides and oxalates are poorly soluble in water. Light and strong Sc-Al alloys developed in the former Soviet Union were used in aircraft such as MIG fighter planes and ballistic missile nose cones during the Soviet era, but after the collapse of the Soviet Union they have been used in lightweight small arms, metal bats, lightweight tent frames, and racing bicycle frames. ScI ₃ [CAS 14474-33-0] is used in metal halide lamps and mercury lamps to adjust the color to daylight. [CAS 7440-20-2]

Source: Morikita Publishing "Chemical Dictionary (2nd Edition)" Information about the Chemical Dictionary 2nd Edition

Japanese:

Sc．原子番号21の元素．電子配置[Ar]3d¹4s²の周期表3族金属元素．希土類元素イットリウム族の一つ．原子量44.955912(6)．質量数45(100％)の安定同位体と，質量数36～60の放射性同位体が知られている．1879年，L.F. Nilsonがガドリン石中から発見し，すぐに，D.I. Mendeleev(メンデレーエフ)の予言したエカホウ素と同一物であることがわかった．元素名はスカンジナビアのラテン語Scandiaから命名．スカンジウムの鉱物には，トルトベイト石Sc₂Si₂O₇がある．地殻中の存在度30 ppm で広く分布しているが，鉱石の品位は低い．タングステン，ウラン製錬の副産物として得られる．希土類中，もっとも高価．主要生産国は中国，カザフスタン，ロシア，ウクライナ．金属は銀白色で2種の変態α(六方最密)，β(立方最密，＞ 950 ℃)がある．融点1541 ℃，沸点2831 ℃．密度2.989 g cm^－3(20 ℃)．酸化数3．標準電極電位 Sc^3＋/Sc－2.03 V．第一イオン化エネルギー6.54 eV．アルミニウムに類似した性質を示すが，希土類元素に分類される．Sc₂O₃，ScX₃，ScOXなどの化合物およびオキソ酸がある．Sc₂O₃･nH₂Oは両性化合物．スカンジウム化合物の塩基性は，イットリウムやランタンなどより弱いため，加水分解しやすく，OHブリッジをもったポリマーをつくる．溶液中では，ScCl₂^＋やScCl^2＋などの錯イオンもあり，いわゆる複塩として，K₂SO₄･Sc₂(SO₄)₃･nH₂Oなども生じる．希土類元素と同様に，フッ化物，シュウ酸塩などは水に難溶．旧ソ連で開発された軽くて強力なSc-Al合金は，旧ソ連時代はMIG戦闘機など航空機，弾道ミサイル・ノーズコーン用材料であったが，ソ連解体後，軽量小火器，金属バット，軽量テントフレーム，レース用自転車フレーム材などとして使われている．ScI₃[CAS 14474-33-0]はメタルハライドランプ，水銀ランプを昼光色に調整するために封入される．[CAS 7440-20-2]