ガドリニウム 化学特性,用途語,生産方法
外観
銀灰色の塊
溶解性
塩酸に溶ける。
解説
Gd．原子番号64の元素．電子配置[Xe]4f 75d16s2の周期表3族ランタノイド元素．希土類元素イットリウム族の一つ．原子量157.25(3)．質量数152(0.20(1)％)，154(2.18(3)％)，155(14.80(12)％)，156(20.47(9)％)，157(15.65(2)％)，158(24.84(7)％)，160(21.86(19)％)の7種の安定同位体と，質量数136～169の放射性同位体が知られている．1880年，C. de Marignacがサマルスキー石から分離した．元素名は，フィンランドの科学者J. Gadolinの名前をとった鉱石ガドリン石からとされる．地殻中の存在度3.3 ppm．ゼノタイム，褐れん石などに含まれる．分離は溶媒抽出法による．高純度( ＞ 99.9999％)のものはイオン交換法が使われる．融点1313 ℃，沸点3266 ℃．密度7.90 g cm－3．第一イオン化エネルギー6.150 eV．金属は293 K 以下で強磁性を示し，0.001 K 程度の極低温をつくる磁気冷却に利用された．GdⅢの化合物のみが知られる．GdⅢの電子配置は4f7で，化合物も強い磁性を示す．水溶液は一般に無色である．ほかの希土類と同じく，シュウ酸塩，リン酸塩，フッ化物，炭酸塩などは水に難溶．EDTA錯体はMRI用の造影剤，(Y，Gd)BO3：Euは赤色，(Y，Gd)BO3：Tbは緑色カラーテレビジョン用または蛍光灯用の蛍光体，Gd2O2Sは小型冷凍機用蓄冷材として用いられる．[CAS 7440-54-2]
森北出版「化学辞典（第2版）
主な性質
- ガリウムは比較的反応性が高く青みがかった白色金属
- ガリウムは酸にも、水酸化ナトリウムにも溶ける
- 金属元素中では水銀、セシウムに次いで融点が低く、手で握ると溶ける
- ガリウムは液体として存在する範囲が約３０℃から２４００℃と最も広い金属（大気中で燃える為、金属材料として使われる事は少ない）
- ヒ素との反応でガリウム?ヒ素化合物半導体を作る
- ガリウム?ヒ素半導体は発光特性、マイクロ波特性、磁気感応性などに特徴があり、電子材料としての利用範囲は広い
用途
新素材研究用。
主な用途
- 半導体チップ、ＬＥＤ?ＬＤチップ（コンピューター、衛星通信装置、オーディオ装置、レーザープリンター、表示素子、光通信装置、ＣＤ、ＭＤ、ＤＶＤ、カメラ、時計、太陽電池）
- 発光素子（パイロットランプ、ディスプレイ表示素子、ＯＡ機器、携帯電話、その他）
- ガリウム合金、酸化ガリウム（歯科合金、超伝導材、ＳＡＷフィルター合金、磁石、スキーワックス、ＴＶ等緑色発光体）
使用上の注意
本品はスピンドル油に浸漬されている。
化学的特性
metal foil, chunks or powder. The powder of gadolinium is highly flammable; incompatible with strong oxidising agents, halogens, acids; and reacts with water or moisture.
物理的性質
Gadolinium is silvery-white, soft, malleable, and ductile with a metallic luster. It is the secondof what is referred to as the dysprosium, subgroup in the middle of the lanthanide seriesof rare-earths. It tarnishes in air, forming the oxide (Gd2O3) on the surface, which flakes offthe surface, exposing a fresh metal that in turn oxidizes.
Its melting point is 1,313°C, its boiling point is 3,273°C, and its density is 7.90g/cm
3.
同位体
There are 39 isotopes of gadolinium. Seven of these are stable. They are: Gd-54, which makes up 2.18% of all the gadolinium found in the Earth’s crust; Gd-55,supplying 14.80%; Gd-156, making up 20.47%; Gd-157, constituting 15.56%; and Gd-158, accounting for 24.85%. In addition, there are two isotopes of gadolinium that areradioactive and with such long half-lives that they still exist in the Earth’s crust. They areregarded as stable isotopes along with the other seven. They are Gd-152 (1.08×10
+14years), which exists in just 0.20% in abundance, and Gd-160 (1.3×10
+21 years), foundin 21.86% abundance.
名前の由来
Named for the mineral gadolinite, which was named for the French
chemist Johann Gadolin.
天然物の起源
Gadolinium is the 40th most abundant element on Earth and the sixth most abundant ofthe rare-earths found in the Earth’s crust (6.4 ppm). Like many other rare-earths, gadoliniumis found in monazite river sand in India and Brazil and the beach sand of Florida as well asin bastnasite ores in southern California. Similar to other rare-earths, gadolinium is recoveredfrom its minerals by the ion-exchange process. It is also produced by nuclear fission in atomicreactors designed to produce electricity.
特性
Gadolinium, unlike most of the rare earths in the dysprosium subgroup, reacts slowlywith water, releasing hydrogen. It is strongly magnetic at low temperatures. Two of its stableisotopes (Gd-155 and Gd-157) have the greatest ability of all natural elements to absorb thermalneutrons to control the fission chain reaction in nuclear reactors. However, few of theseisotopes are found in the ores of gadolinium.
使用
Gadolinium’s main use is based on its ability to absorb neutrons, thus making it ideal as aneutron-shielding and neutron-absorbing metal. It is also used as an alloying agent for steel andother metals to make the metals more workable and to be able to withstand low temperatures.
Gadolinium is used in the manufacture of electronics and can be combined with yttriumto make garnets used in microwaves. Gadolinium is used as a catalyst to speed up chemicalreactions, and to activate phosphor compounds in TV screens and cast filaments in electricaldevices. It is also used in high-temperature furnaces. Gadolinium is paramagnetic at normalroom temperatures (weaker than ferromagnetic) and becomes strongly ferromagnetic at verycold temperatures.
定義
A ductile
malleable silvery element of the lanthanoid
series of metals. It occurs in association
with other lanthanoids. Gadolinium is
used in alloys, magnets, and in the electronics
industry.
Symbol: Gd; m.p. 1313°C; b.p.
3266°C; r.d. 7.9 (25°C); p.n. 64; r.a.m.
157.25.
危険性
The halogens of gadolinium are very toxic, and gadolinium nitrate is explosive. As withmost rare-earths, care should be taken not to inhale fumes or ingest particles of gadolinium.
ガドリニウム 上流と下流の製品情報
原材料
準備製品