-
解説
テルル化ビスマス，一般には，Bi2Te3であるが，そのほかにBi14Te6(hedleyite，六方晶系)や，合成で得られたBiTe，Bi2Teがある．Bi2Te3(800.76)は，天然にはテルルビスマス鉱(tellurobismuthite)として産出する．計算量のBiとTeとを石英ガラス管中で数日間，475 ℃ に加熱すると得られる．灰色の三方晶系板状結晶．融点585 ℃．密度7.74 g cm－3．蒸気はニンニク臭があり，有毒で眼や皮膚をおかす．半導体で，Bi過剰でp型に，Te過剰でn型になる．電気抵抗率3.3×10－4 Ω cm．バンドギャップ0.13 eV(300 K)で狭い．熱伝導率は小さく，熱起電力が大きい．半導体として電子工学材となる．たとえば，熱電冷却素子，熱電発電素子などに用いられる．
-
化学的特性
Bismuth telluride is a gray or black crystalline
solid or gray powder.
-
使用
Bi2Te3, along with Sb2Te3 and other structurally analogous semiconductors, is widely regarded as one of the best materials for room-temperature thermoelectric devices. Bismuth(III) telluride is a key component of thermoelectric materials that have reached ZT values as high as 2.4 at room temperature.
-
一般的な説明
Gray or black hexagonal platelets with a metallic luster or gray powder. Mp: 586°C. Density: 7.8 g cm-3. An alloy of two metallic elements.
-
反応プロフィール
BISMUTH TELLURIDE may emit toxic fumes of tellurium when heated to decomposition. Incompatible with strong oxidizing agents such as nitric acid or bromine, chlorine or fluorine. Moderate fire hazard by reaction with such materials. May react with strong acids to evolve toxic gases; may react slowly with water to evolve toxic gases. Slight explosion hazard with moisture.
-
危険性
Toxic.
-
健康ハザード
Bismuth telluride, either alone
or doped with selenium sulfide, is apparently of
very low toxicity.
In limited industrial experimental work
with bismuth telluride under controlled conditions
(vacuum hoods), no adverse health
effects were encountered other than tellurium
breath.
-
職業ばく露
Bismuth telluride is used in thermoelectric
cooling, power generation, semiconductor manufacture;
pharmaceuticals; medical therapy; cosmetics.
Exposure involves those working in “Silicon Valley” and
similar locations around the world. An alloy of two metallic
elements that are sometimes doped with SeS. The SeS
dopant alters the electrical properties, but has too low a
concentration to affect the chemical properties.
-
輸送方法
UN3284 Tellurium compound, n.o.s., Hazard
Class: 6.1; Labels: 6.1—Poisonous materials, Technical
Name Required.
-
不和合性
Reacts with acids forming toxic gases.
Incompatible with oxidizers (chlorates, nitrates, peroxides,
permanganates, perchlorates, chlorine, bromine, fluorine,
etc.); contact may cause fires or explosions. Keep away
from alkaline materials, strong bases, strong acids, oxoacids,
epoxides. Toxic and flammable gas may slowly
evolve from contact with moisture.
