タリウム 化学特性,用途語,生産方法
主な性質
- タリウムは外観、性質、比重等が鉛によく似ている（ナイフで切れるほど柔質）
- 乾燥した空気中では安定であるが、高温になると酸化し易い。水素、窒素、炭素とは直接反応しないが、フッ素、塩素等のハロゲン類には反応する
- タリウムは強毒性。空気や水に容易に溶けて水溶性化合物を発生（人の皮膚の湿気でこの反応が起こり中毒を起こす事がある）
- 利用の大半は酸化及びフッ化タリウムの形である
解説
タリウム，元素記号 Tl ，原子番号 81，原子量 204.3833。周期表 13族に属する。 1861年イギリスの物理学者で，化学者の W.クルックスにより，ドイツのハルツ地方の硫酸工場の鉛室沈殿中から分光分析により発見された。スペクトル線が若葉を思わせる黄緑色であったことから，ギリシア語の若葉に相当するタロスにちなんで命名された。地殻存在量 0.5ppm，海水中の存在量は 0.001 μg/l 。単体は青白色の非常に軟らかい金属で，空気中では表面が酸化し，酸化膜は厚くなるので，石油中に保存することが多い。合金をつくりやすく，水銀とも容易にアマルガムをつくる。比重 11.85。 174℃で蒸発しはじめる。融点 303.5℃。原子価は1価，3価。低融点合金，軸受合金などに利用されるほか，硫酸塩は殺鼠剤，殺虫剤として用いられる。
主な用途
- 硫酸タリウム（殺鼠剤）
- 酸化及びフッ化タリウム（低融点ガラス）
- 合金添加元素（電子材料）
存在度
地殻中の存在度0.36 ppm．K＋ と同型置換するためカリ長石，雲母などに広く薄く分布するが，親銅元素で，銅，亜鉛，鉛などの硫化鉱物中に伴われて産出するので，これら金属の精錬の際に煙道じんまたは残さから副産物として得られる．硫酸塩飽和水溶液の電解により金属がつくられる．希少鉱物としてTlAsS2(ローランダイト)，(Cu,Tl,Ag)2Se(クルックス石)などがある．α(六方最密)，230 ℃ 以上でβ(体心立方)の2変態が知られる．鉛に似た軟らかい白色の金属．融点304 ℃，沸点1457 ℃．密度11.85 g cm－3(20 ℃)．金属は硫酸，硝酸には可溶，塩酸には溶けない．酸化数1，3．第一イオン化エネルギー6.108 eV．TlⅠは，アルカリ金属および銀に似ており，水酸化物TlOHはかなり強い塩基で，ハロゲン化物は感光性があり，フッ化物以外は水に難溶である．空気中で容易に酸化されて黒色のTl2Oを生じ，Tl2Oは水と接触して黄色のTlOHとなる．標準電極電位 Tl＋/Tl－0.3363 V，Tl3＋/Tl＋＋1.25 V．したがって TlⅢは容易に TlⅠに還元されるが，TlⅠを TlⅢに酸化するにはMnⅦ O4－，Cl2 のような強力な酸化剤が必要である．Tlの原子価殻は6s26p1で6p電子は容易に失われるか，結合にあずかれるが，6s2は安定で TlⅢにはなりにくいので，タリウム(Ⅰ)化合物のほうが多く知られる．TlⅠClを水懸濁液やアセトニトリル溶液中で，Cl2 で酸化するとTlⅢ Cl3が得られる．TlⅢは同族の AlⅢなどと異なりHSAB原理による軟酸にあたるので，R－(R ＝ アルキル)など軟塩基と錯体をつくりやすい．R3TlⅢ(R ＝ メチル，エチル，イソブチルなど)が知られている．TlⅢ Cl3も [TlⅢCl4]－ となりやすく，錯化合物のほうが安定である．
説明
Thallium was discovered in 1861 by Sir William Crookes (and
independently by Claude-Auguste Lamy a year later) and
occurs in the lithosphere at 0.7 ppm. The name thallium is in
reference to the particularly bright green spectral lines seen in
the spectra resultant from a flame spectroscopy test (from
Greek thallos, meaning a green shoot or twig), the one used in
its discovery. Thallium is a heavy metallic element that exists in
the environment mainly combined with other elements
(primarily oxygen, sulfur, and the halogens) in inorganic
compounds.
化学的特性
Thallium is a soft, bluish-white, heavy, very soft metal insoluble in water and organic solvents. It turns gray on exposure to air.
物理的性質
Thallium has much the same look (silvery) and feel as lead and is just as malleable. Unlikelead, which does not oxidize readily, thallium will oxidize in a short time, first appearing as adull gray, then turning brown, and in just a few years or less turning into blackish corrodedchunks of thallium hydroxide. This oxide coating does not protect the surface of thalliumbecause it merely flakes off exposing the next layer to oxidation.
Thallium is just to the left of lead in period 6, and both might be considered extensionsof the period 6 transition elements. Thallium’s high corrosion rate makes it unsuitable formost commercial applications. Its melting point is 304°C, its boiling point is 1,473°C, andits density is 11.85 g/cm
3.
同位体
There are a total of 55 isotopes for thallium. All are radioactive with relativelyshort half-lives, and only two are stable. The stable ones are Tl-203, which constitutes29.524% of the element’s existence in the Earth’s crust, and Tl-205, which makes up70.476% of the element’s natural abundance found in the Earth’s crust.
名前の由来
From the Greek word thallos, meaning “young shoot” or “green twig.”
Named for the green spectral line produced by the light from the element in a spectroscope.
天然物の起源
Thallium is the 59th most abundant element found in the Earth’s crust. It is widely distributedover the Earth, but in very low concentrations. It is found in the mineral/ores ofcrooksite (a copper ore; CuThSe), lorandite (TlAsS
2), and hutchinsonite (lead ore, PbTl). Itis found mainly in the ores of copper, iron, sulfides, and selenium, but not in its elementalmetallic state. Significant amounts of thallium are recovered from the flue dust of industrialsmokestacks where zinc and lead ores are smelted.
特性
Elemental thallium metal is rare in nature mainly because it oxidizes if exposed to air (oxygen)and water vapor, forming thallium oxide, a black powder. Although some compounds ofthallium are both toxic and carcinogenic, they have some uses in the field of medicine. Somecompounds have the ability to alter their electrical conductivity when exposed to infraredlight.
使用
Thallium is used in photoelectric cells, insemiconductor studies, and in low-rangeglass thermometers. It is alloyed with manymetals. Many of its salts are used as rodent poisons. Radioactive thallium-201 is used fordiagnostic purposes in nuclear medicine inpatients with coronary artery disease.
定義
A soft malleable
grayish metallic element belonging to
group 13 of the periodic table. It is found
in lead and cadmium ores, and in pyrites
(FeS
2). Thallium is highly toxic and was
used previously as a rodent and insect poison.
Various compounds are now used in
photocells, infrared detectors, and lowmelting
glasses.
Symbol: Tl; m.p. 303.5°C; b.p. 1457°C;
r.d. 11.85 (20°C); p.n. 81; r.a.m.
204.3833.
調製方法
Thallium sulfide is insoluble in alkaline solution, but soluble in acid,
allowing its separation from group I elements. Thallium
chloride is only slightly soluble in cold water, which permits
its separation from chlorides of cadmium, copper, tellurium,
and zinc.
Thallium metal may be obtained from the compounds in
several ways: by electrolysis of carbonates, sulfates, or
perchlorates; by precipitation of metallic thallium with
zinc; and by reduction of thallous oxalate or chloride. A
number of industrial processes for the recovery of thallium
have been described in the literature. Several of them depend
on the extraction of thallium from flue dust by boiling it in
acidified water.
作用
タリウムはKの関与する生理作用を阻害するため，神経系，肺，肝臓，腎臓などに対する毒性が強く(致死量1 g)，カドミウムより4けたも危険とされる．PRTR(環境汚染物質排出移動登録)法・第二種化学物質として，経口クラス2，作業環境クラス2，生態クラス1の指定を受けている(1がもっとも厳しい)．従来の用途は，殺鼠剤，殺虫剤，顔料木材防腐剤などであったが，人体に対する毒性のために使用量が減った．放射線測定用シンチレーションカウンター用のシンチレーター賦活剤として，レーザー発振用タリウム系Ⅲ-Ⅴ族半導体，光電管，水銀との合金は低温(－60 ℃ まで)でもはたらく電流開閉器に，酸化タリウムは高屈折率ガラス(光ファイバー用)などとして使われる．転移温度95～128 K のTl，Ba，Caを含む一連の酸化銅系高温超伝導体が知られ，Ba2CaCu2Tl2O8薄膜は携帯電話基地局受信用マイクロ波フィルターとして実用化されている．(Hg0.8Tl0.2)Ba2Ca2Cu3O8.33は定比化合物最高の転移温度138 K を示す．
一般的な説明
Bluish-white soft malleable metal or gray granules. Density 11.85 g / cm3. Emits toxic fumes when heated. May be packaged under water.
空気と水の反応
Flammable in the form of powder or dust. Insoluble in water.
反応プロフィール
THALLIUM is a reducing agent. Reacts so vigorously with fluorine that the metal becomes incandescent [Mellor 5:421 1946-47].
危険性
In all forms, thallium is very toxic if inhaled, when in contact with the skin, and in particular,if ingested. Mild thallium poisoning causes loss of muscle coordination and burningof the skin, followed by weakness, tremor, mental aberration, and confusion.
Thallium disease (thallotoxicosis) results from the ingestion of relatively large doses (morethan a few micrograms). The severity may vary with the age and health of the patient. Nervesbecome inflamed, hair is lost, the patient experiences stomach pain, cramps, hemorrhage,rapid heartbeat, delirium, coma, and respiratory paralysis. The disease has the potential tocause death in about one week. In the past thallium was one of the poisons of choice used bymurderers because it acts slowly and makes victims suffer. In 1987 then Iraqi dictator SaddamHussein’s agents mixed thallium powder in orange juice or yogurt and fed it to people heperceived to be his enemies. There were at least 40 thallium poisonings, mostly of Kurdishleaders. (William Langewiesche, “The Accuser,” Atlantic, March 2005, 56.)
健康ハザード
Thallium and its soluble compounds arehighly toxic in experimental animals. Theacute toxic symptoms in humans are nausea,vomiting, diarrhea, polyneuritis, convulsion,and coma. Ingestion of 0.5 g can be fatalto humans. Severe chronic toxicity can leadto kidney and liver damage, deafness, andloss of vision. Other signs of toxicity fromchronic exposure include reddening of theskin, abdominal pain, polyneuritis, loss ofhair, pain in legs, and occasionally cataracts.Ingestion of thallium salts in children hascaused neurological abnormalities, mentalretardation, and psychoses.
Hoffman (2000) reviewed thallium poisoningin women during pregnancy and cited acase that began in the first trimester of pregnancyresulting in fetal demise. John Peter andViraraghavan (2005) have reviewed toxicityof thallium and public health risk and discussedenvironmental concerns and variousremoval technologies from aquatic system.
.
安全性プロファイル
Human poison by unspecified route. Human systemic effects by ingestion: nerve or sheath structural changes, extra-ocular muscle changes, sweating, and other effects. Flammable in the form of dust when exposed to heat or flame. Violent reaction with F2. When heated to decomposition it emits toxic fumes of Tl. Used as a rodenticide and fungicide, and in lenses and prisms, in highdensity liquids. See also THALLIUM COMPOUNDS and POWDERED METALS.
職業ばく露
Thallium is usually obtained as a byproduct from the flue dust generated during the roasting of pyrite ores in the smelting and refining of lead and zinc. Thallium has not been produced in the United States since 1984, but is imported for use in the manufacture of electronics, optical lenses, and imitation precious jewels. It also has use in some chemical reactions and medical procedures. Thallium and its compounds are used as a rodenticide and fungicide; in the manufacture of plates and prisms, high-density liquids; as insecticides, catalysts; in certain organic reactions, in phosphor activators; in bromoiodide crystals for lenses, plates, and prisms in infrared optical instruments; in photoelectric cells; in mineralogical analysis; alloyed with mercury in low-temperature thermometers, switches and closures; in high-density liquids; in dyes and pigments; in fire-works; and imitation precious jewelry. It forms a stainless alloy with silver and a corrosion-resistant alloy with lead. Its medicinal use for epilation has been almost discontinued. Highly persistent in the environment. Note: Thallium was used in the past as a rodenticide, it has been banned in the United States due to its toxicity from accidental exposure. In some countries, thallium(I)sulfate(2:1) is still used as a rat poison and ant bait.
発がん性
Female mice treated orally or
cutaneously with high doses of thallium showed a degenerative
process in the genital tract similar to that found in
castrated animals or after uterine denervation. The diagnoses
were papilloma, precancerous lesions, and cancer. The control
mice did not develop cancer.
環境運命予測
Metallic thallium (TI) is bluish white or gray; it is very soft
and malleable. The element can exist in the environment
mainly combined with other elements (primarily oxygen,
sulfur, and the halogens) in inorganic compounds. Thallium
exists in monovalent (thallous, thallium (I), Tl
+1) and
trivalent (thallic, thallium (III), Tl
+3) states. Monovalent
thallium ions also are more stable in aqueous solution, but
trivalent thallium (Tl
+3) can be stabilized by complexing
agents. Monovalent thallium is similar to potassium (K
+) in
ionic radius and electrical charge, which contribute to its
toxic nature.
Compounds of thallium, however, are generally soluble in
water and the element is found primarily as the monovalent
ion (Tl
+). Thallium tends to adsorb to soils and sediments,
and to bioconcentrate in aquatic plants, invertebrates, and
fish. Terrestrial plants can also absorb thallium from soil. Thallium is quite stable in the environment because it is
neither transformed nor biodegraded. However, thallium may
be bioconcentrated by organisms from water. The US Environmental
Protection Agency has identified several National
Priorities List sites polluted by thallium.
輸送方法
Thallium: UN3288 Toxic solids, inorganic, n.o.s., Hazard Class: 6.1; Labels: 6.1-Poisonous materials, Technical Name Required. UN1707 Thallium compounds, n.o.s., Hazard Class: 6.1; Labels: 6.1-Poisonous materials, Technical Name Required.
不和合性
Varies. Cold thallium ignites on contact with fluorine. Thallium metal reacts violently with strong acids (such as hydrochloric, sulfuric, and nitric) and strong oxidizers (such as chlorine, bromine, and fluorine). Cold thallium ignites on contact with fluorine. Reacts with other halogens at room temperature.
廃棄物の処理
Consult with environmental regulatory agencies for guidance on acceptable disposal practices. Generators of waste containing this contaminant (≥100 kg/mo) must conform with EPA regulations governing storage, transportation, treatment, and waste disposal. Dilute thallium solutions may be disposed of in chemical waste landfills. When possible, thallium should be recovered and returned to the suppliers.
タリウム 上流と下流の製品情報
原材料
準備製品