テルル(IV)ジオキシド 化学特性,用途語,生産方法
外観
白色～わずかにうすい褐色, 粉末
溶解性
水に不溶。水酸化ナトリウム溶液, 塩酸に易溶。水酸化ナトリウム溶液及び塩酸に溶けやすく、アンモニア水及び水に極めて溶けにくい。
解 説
二酸化テルル：TeO2(159.60)．テルルを熱硝酸で処理してHNO3･2TeO2とし，これを熱して硝酸を除いて得られる．不揮発性の白色の固体．350 ℃ 以下で得られるものは正方晶系ルチル型構造．密度5.66 g cm－3(0 ℃)．350 ℃ 以上の高温で得られるものは斜方晶系(板チタン石に似る)．密度5.89 g cm－3(0 ℃)．一定の融点を示さず733 ℃ 付近で暗黄色の液体になる．水に難溶．両性酸化物で，濃強酸と作用してTe2O3(OH)NO3のような水酸化物塩を，また強アルカリ水溶液では亜テルル酸塩を生じる．酸化剤，光触媒，電子材料，光偏光素子，光記録素子材料(光ディスクメモリー)などに用いられる.
用途
酸化剤、触媒、電子材料、テルル化合物の原料。
化学的特性
Heavy, white, crystalline powder; odorless. Soluble in concentrated
acids, alkalies; slightly soluble in dilute
acids, water.
物理的性質
White crystals; dimorphic; exists in tetragonal and orthorhombic forms; density 5.75 g/cm
3 (tetragonal), 6.04 g/cm
3 (orthorhombic); melts at 733°C forming a deep yellow liquid; vaporizes at 1,245°C; insoluble in water; soluble in acids and alkalies.
使用
Tellurium dioxide is also used in devices which can convert light into sound (acousto-optic material). Glasses made of tellurium oxide have high refractive indices and transmit into mid-IR region. It is used to make glasses with special properties. It is useful in optical waveguides and optical fiber amplification.
調製方法
Tellurium dioxide in its orthorhombic form occurs in nature as mineral tellurite. It is mined from natural deposits. Also, tellurium dioxide is produced as an intermediate during recovery of tellurium metal from anode slimes of electrolytic copper refining (See Tellurium, Production). The dioxide also is prepared by treating tellurium metal with hot nitric acid to form 2TeO
2?HNO
3. The product then is heated to drive off nitric acid.
一般的な説明
Tellurium dioxide (TeO
2) is a ceramic material that can be used as a semiconducting oxide. It has a wide band gap and high mobility as determined by density functional theory (DFT) calculations. In bulk quantity, it exists in two polymorphs which include tetragonal α-TeO
2 and orthorhombic β-TeO
2.
安全性プロファイル
Poison by intratracheal route. An experimental teratogen. Experimental reproductive effects. When heated to decomposition it emits toxic fumes of Te. See also TELLURIUM COMPOUNDS.
純化方法
Dissolve it in 5M NaOH, filter it and precipitate it by adding 10M HNO3 to the filtrate until the solution is acid to phenolphthalein. After decanting the supernatant, the precipitate is washed five times with distilled water, then dried for 24hours at 110o [Horner & Leonhard J Am Chem Soc 74 3694 1952].
テルル(IV)ジオキシド 上流と下流の製品情報
原材料
準備製品