Bromine - Bromine

Br. Atomic number 35. Nonmetallic element in group 17 of the periodic table with electron configuration [Ar]3d ¹⁰ 4s ² 4p ^5. Atomic weight 79.904(1). One of the halogen elements. Stable natural isotopes with mass numbers 79 (50.69(7)%) and 81 (49.31(7)%) exist, as well as radioactive isotopes with mass numbers 67 to 97. It is the only nonmetallic element that is liquid at room temperature, and was discovered in bittern by French chemist AB. Balard in 1826. Its English name comes from the Greek word βρμο (bromos), which means bad smell. In his book "Syamitsu Kaisou" published in 1837, Udagawa Yoan called it Flomium.
It does not exist in its elemental form in nature, but exists mainly as bromides of alkali metals and alkaline earth metals, together with chlorine, in much smaller amounts than chlorine. It is also found in an average of 67 mg per liter of seawater. The main producers are the United States (42%), followed by Israel (36%) (2007), and the reserves are in the United States, France, and Spain, in that order. It is produced by adding chlorine to seawater, bittern, brine, or the mother liquor from which salt is separated from rock salt. Its elemental form is the diatomic molecule Br ₂ in the solid, liquid, and gas phases. It is a reddish-brown, irritating liquid. It is highly volatile, releasing reddish-brown vapor at room temperature. Density 3.1226 g cm ^-3 (liquid at 20 °C), 7.59 g L ^-1 (gas at 25 °C). Melting point -7.2 °C, boiling point 58.78 °C. Br-Br 0.22811 nm. First ionization energy 11.814 eV. The ionic radius of ^Br- is 0.196 nm. Its solubility in 100 g of water is 3.58 g (293 K), but its solubility in water is low at 0.046% (293 K). It dissolves well in alkaline bromide solutions as the tribromide ion _Br3- ^. It is easily soluble in common organic solvents such as alcohols, ether, benzene, and carbon tetrachloride. It is more stable than chlorine water, but in aqueous solutions it undergoes partial hydrolysis to produce hypobromous acid and hydrobromic acid. Its oxidation numbers are -1, 1, 3, 5, and 7 (e.g. HBr, HBrO, _HBrO2 , _HBrO4 ). It reacts with hydrogen by heating or exposure to light to produce HBr. It reacts with fluorine to produce BrF, _BrF3 , _BrF5, etc., and also reacts with chlorine and sulfur to produce BrCl and _S2Br2 . It has an oxidizing effect, oxidizing ammonia to _N2 and sulfur dioxide to sulfuric _acid . ^Br- is oxidized by _Cl2 to _Br2 , and _Br2 oxidizes ^I- to _I2 . It reacts with many metals at room temperature or high temperatures to form bromides. It has an oxidizing effect on organic compounds, and adds to and replaces hydrogen in unsaturated compounds.
Although its oxidizing power is weaker than that of chlorine, it is used as an oxidizing agent, disinfectant, and brominating agent, and as a raw material for many inorganic and organic bromine products, and is particularly important as a raw material for photographic materials and pharmaceuticals. Brominated flame retardants have been widely used in electronic and home appliances, but production has decreased since restrictions were imposed in the EU and the United States. Liquid bromine and its vapor can cause damage to the upper respiratory tract and lung tissue on contact. Designated as a hazardous substance under the Poisonous and Deleterious Substances Control Act. [CAS 7726-95-6][See alternative terms] Production of bromine

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

Br．原子番号35の元素．電子配置[Ar]3d¹⁰4s²4p⁵の周期表17族非金属元素．原子量79.904(1)．ハロゲン元素の一つ．天然には質量数79(50.69(7)％)，81(49.31(7)％)の安定核種があり，ほかに質量数67～97の放射性同位体がある．常温で液体である唯一の非金属元素で，1826年フランスの化学者A-B. Balardによってにがりのなかから発見された．英語名は悪臭を意味するギリシア語βρμο(bromos)に由来する．宇田川榕菴は天保8年(1837年)に出版した「舎密開宗」で，蒲羅密烏母(フロミウム)としている．
天然には単体として存在せず，主としてアルカリ金属およびアルカリ土類金属の臭化物として，塩素よりはるかに少量ではあるが塩素とともに存在する．また海水1 L 中に平均67 mg 含まれている．生産国はアメリカ(42％)，ついでイスラエル(36％)(2007年)，埋蔵量はアメリカ，フランス，スペインの順である．海水，にがり，かん水あるいは岩塩より食塩を分離した母液に塩素を通じてつくられる．単体は固相，液相，気相のいずれでも二原子分子 Br₂ である．赤褐色の刺激性の液体．揮発しやすく，室温で赤褐色の蒸気を放つ．密度3.1226 g cm^－3(液体20 ℃)，7.59 g L^－1(気体25 ℃)．融点－7.2 ℃，沸点58.78 ℃．Br-Br0.22811 nm．第一イオン化エネルギー11.814 eV．Br^－ のイオン半径は0.196 nm．水100 g に対する溶解度は3.58 g(293 K)であるが，一方，臭素に対する水の溶解度は0.046％(293 K)と低い．臭化アルカリ溶液には三臭化物イオン Br₃^－ となってよく溶ける．アルコール類，エーテル，ベンゼン，四塩化炭素などの一般の有機溶媒に易溶．塩素水より安定であるが，水溶液中では一部加水分解して次亜臭素酸と臭化水素酸を生じる．酸化数－1，1，3，5，7(例：HBr，HBrO，HBrO₂，HBrO₄)．水素とは加熱または光照射によって反応してHBrを生成する．フッ素と反応してBrF，BrF₃，BrF₅などをつくり，塩素，硫黄とも反応してBrCl，S₂Br₂をつくる．酸化作用があり，アンモニアを N₂ に，二酸化硫黄を硫酸に酸化する．Br^－ は Cl₂ によって酸化され Br₂ となり，Br₂ は I^－ を I₂ に酸化する．多くの金属と室温または高温で反応し臭化物をつくる．有機化合物に対しては酸化作用をもち，不飽和化合物には付加，また水素を置換する．
塩素より酸化力は弱いが，酸化剤，殺菌剤，臭素化剤として，また多くの無機，有機臭素製品の原料として用いられ，とくに写真材料，医薬品の原料として重要である．臭素化物難燃剤が電子機器・家電製品に多用されてきたが，EU・アメリカで規制が行われるようになり，生産量が減っている．液体臭素やその蒸気は触れると上気道，肺組織に障害を起こす．毒物劇物取締法・劇物指定．[CAS 7726-95-6][別用語参照]臭素の製造

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