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外観
無色澄明の液体
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定義
本品は、硝酸の銀塩であり、次の化学式で表される。
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解説
硝酸銀．金属銀を硝酸に溶解後，溶液を蒸発すると得られる．無色の斜方晶系板状晶．密度4.35 g cm－3．159.6 ℃ 以上で六方晶系(密度4.19 g cm－3)に転移する．融点212 ℃．融点以上に加熱するとAgNO2と O2 になり，さらに440 ℃ で加熱するとAgとNO2になる．水に易溶，エタノールに微溶．有機物が共存しなければ，固体も水溶液も光に対して安定である．銀めっき材料，写真感光剤，分析試薬，殺菌剤，触媒，鏡，インキ製造，外用医薬などに用いられる．タンパク質凝固作用があり，皮膚，組織をおかす．有毒．
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用途
銀塩原料、写真感光材料、写真製版原料、医薬
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化粧品の成分用途
殺菌剤、着色剤
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合成
硝酸銀は硝酸に銀を溶解させると合成可能で、蒸発や乾燥によって得られます。この反応では濃硝酸を用いるとが発生し、希硝酸を用いるとが生じます。工業的にもこの方法で、硝酸銀が製造されています。
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効能
殺菌消毒薬, 皮膚軟化薬
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商品名
硝酸銀 (マイラン製薬)
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化学的特性
Silver nitrate, AgN03, is colorless,transparent,tabular,rhombic crystals that become gray or grayish-black on exposure to light in the presence of organic matter.It is odorless with a bitter,caustic,metallic taste. It is caustic,and a strong oxidizing agent that is soluble in cold water, more soluble in hot water, glycerol,and hot alcohol,slightly soluble in ether,and decomposes at boiling point Used in photographic film, silver plating,silvering mirrors,and as an antiseptic.
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物理的性質
Colorless, transparent, large rhombohedral crystals, or white small crystals; bitter, caustic metallic taste; odorless; pure compound is not sensitive to light but trace organics promote photo reduction, turning the salt to grayish black on exposure to light; density 4.35 g/cm3; melts at 212°C; decomposes at 440°C; very soluble in water, soluble in ethanol and acetone.
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使用
The basis of nearly all photographic silver halides with the
exception of the daguerreotype process, silver nitrate is a
heavy white crystal made by dissolving elemental silver in
nitric acid followed by evaporation. It is soluble in water, ether,
and glycerin. Silver nitrate is not sensitive to light, but when
combined with an organic material, a halogen, or a halide it
will reduce back to a metallic state when exposed to light.
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適応症
Silver nitrate, 0.1% to 0.5%, is an excellent germicide and astringent. Its
germicidal action is due to precipitation of bacterial protein by liberated silver
ions. It may cause pain if applied in concentrations >0.5%.
Silver nitrate is another cauterizing agent and coagulates cellular protein and
removes granulation tissue. This should be applied everyday for approximately
5 days."
"Silver nitrate (AgNO3), in solid form or in solutions stronger than 5%, is used for
its caustic action; 5% to 10% solutions may be applied to fissures or excessive
granulation tissue. Silver nitrate sticks consist of a head of toughened silver nitrate (>94.5%) prepared by fusing the silver salt with sodium chloride. They
are dipped in water and applied as needed.
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製造方法
Silver nitrate is prepared by dissolving silver metal in dilute nitric acid. The solution is evaporated and residue is heated to dull red heat with concentrated nitric acid to decompose impurities such as copper nitrate. Residue then is dissolved in water, filtered, and recrystallized to obtain pure silver nitrate.
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性質
光に安定であるが、有機物に触れると還元されて銀を析出し黒色となる。酒石酸、ショ糖、アルデヒドなどにより、アンモニアアルカリ性水溶液を還元するとガラス壁などに銀鏡をつくることができる。タンパク凝固作用があり、皮膚、組織を腐食するが、このことはきわめて古くから知られており（700年ごろにつくられている）、硝酸銀棒のことをlunar causticといっている。
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用途
写真工業での臭化銀製造の原料として広く用いられており、銀めっき、銀鏡の製造原料として用いられる。医薬品としては外用として防腐剤、収斂剤(しゅうれんざい)、化学では各種試薬として、そのほか陶磁器の着色用に用いられる。
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一般的な説明
A colorless or white crystalline solid becoming black on exposure to light or organic material.
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空気と水の反応
Water soluble.
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反応プロフィール
Silver nitrate is noncombustible but, as an oxidizing agent, can accelerate the burning of combustible materials. If large quantities are involved in a fire or the combustible material is finely divided, an explosion may result. Prolonged exposure to fire or heat may result in an explosion. Toxic oxides of nitrogen are produced in fires. Light sensitive. Mixtures with alkyl esters may explode owing to the formation of alkyl nitrates. Mixtures with phosphorus, tin(II) chloride, or other reducing agents may react explosively [Bretherick 1979 p. 108-109]. Reacts with acetylene in the presence of ammonia to form silver acetylide, a powerful detonator when dry [Bretherick 1979 p. 198]. Reaction with ethyl alcohol (or other alcohols) may produce silver fulminate, which can explode when disturbed [Bretherick 1979 p. 200]. An intimate mixture of Silver nitrate and magnesium may ignite spontaneously on contact with a drop of water [Bretherick 1979 p. 200]. An explosion occurred when purified phosphine was passed rapidly into a concentrated solution of Silver nitrate [Mellor 3:471 1946-47]. When a mixture of 28% ammonium hydroxide and Silver nitrate solution was treated with a small amount of sodium hydroxide. Black precipitate, silver nitride exploded on stirring [MCA Case History 1554 1968].
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危険性
Strong irritant to skin and tissue.
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健康ハザード
Concentrated solutions will produce irritation, ulceration, and discoloration of the skin; also causes severe irritation of the eyes. Ingestion will produce violent abdominal pain and other gastroenteric symptoms.
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火災危険
Behavior in Fire: Increases flammability of combustibles.
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銀鏡反応
硝酸銀を用いた銀鏡反応
硝酸銀を含むアンモニアアルカリ性水溶液を、ショ糖や、アルデヒドなどによって還元すると、ガラス壁などに銀鏡を作成可能です。アンモニア性硝酸銀水溶液がホルミル基を有する化合物を酸化し、カルボン酸になることで、還元された銀が析出するためです。
この反応は銀鏡反応 (英: silver mirror reaction) と呼ばれています。なお、銀鏡反応は、めっきに利用されます。
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注意点
硝酸銀を使用する際の注意点
液体アンモニアやアンモニア水などに硝酸銀を反応させると、徐々に雷銀 (英: fulminating silver) と呼ばれる黒色結晶が生じます。雷銀とは、AgNH2とAg3Nの混合物のことです。
雷銀はとても敏感な化合物なので、わずかな摩擦や熱でも水溶液中が爆発します。とくにナトリウムイオンの存在下では、雷銀の生成が促進されます。
そのため、と硝酸銀が混ざった廃液や銀鏡反応後の廃液だけでなく、誤って雷銀を作った場合などにも、や塩化ナトリウム水溶液によって分解して、雷銀を処分することが必要です。
硝酸銀の加工によって、起爆剤が作られます。実際に大阪府の魔法瓶製造会社から100kgの硝酸銀が盗まれたときには、爆弾闘争に過激派が利用する可能性も考えて、大阪府警察内に異例の捜査本部が設置されました。
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使用用途
1. 写真工業分野
写真工業分野では、感光材料である臭化銀製造の原料として広く用いられています。
2. 医薬品分野
医薬品分野では、外用として防腐剤や収斂剤に使用されている他、新生児の治療対策として点眼薬や口内炎、歯頸部知覚過敏症などの薬に使用されています。
3. 化学分野
化学分野では、分析試薬や一般試薬としても利用可能です。具体的には、硝酸銀は塩化物と反応すると(I) (AgCl) の白色沈殿を生成するため、塩化物イオンの検出のために使用できます。
その他、銀めっきや銀鏡の製造原料、各種銀塩の製造、殺菌剤、触媒、毛髪染め、陶磁器の着色、インキ製造、電気接点材料などの使用用途もあり、その分野は非常に幅広いです。
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応用例（製薬）
Silver nitrate (AgNO3), after salicylic acid, is widely used for the treatment of warts. AgNO3 is a highly
water-soluble salt, which readily precipitates as AgCl, black in colour, when in contact with the skin. Warts
are caused by a human papillomavirus, and mostly hands, feet and the anogenital areas are affected. The
treatment is based on the destruction of the local tissue, and the silver salt is applied via a caustic pen to the
affected area. Silver nitrate is highly corrosive and is known to destroy these types of tissue growth. Care has
to be taken when this treatment option is used, as the resulting AgCl stains any skin or fabric which it has
been in contact with.
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安全性プロファイル
A human poison. Experimental poison by ingestion, intravenous, subcutaneous, and intraperitoneal routes. Experimental reproductive effects. Human mutation data reported. A severe eye irritant. A powerful caustic and irritant to skin, eyes, and mucous membranes. Swallowing can cause severe gastroenteritis that may be fatal. Questionable carcinogen with experimental tumorigenic data. A powerful oxidizer. Incompatible with acetylene, acetylides, alkalies, aluminum, antimony salts, arsenic, arsenites, bromides, carbon, carbonates, chlorides, ClF3, chlorosulfuric acid, copper, creosote, ethanol, ferrous salts, hypophosphites, iodides, Mg powder with H20, morphme salts, NH3 with KOH to yield black Ag3N, oils, PH3, phosphates, phosphonium iodide, phosphorus, plastics, sulfur, tannic acid, tartrates, thiocyanates, vegetable decoctions and extracts, zinc with NH3 with KOH. When heated to decomposition it emits toxic fumes of NOx. See also SILVER COMPOUNDS and NITRATES
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職業ばく露
Silver nitrate is used in photography, silver plating; as an antiseptic; in chemical reactions; and mirror manufacturing; as starting material in production of other silver compounds.
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輸送方法
UN1493 Silver nitrate, Hazard Class: 5.1; Labels: 5.1-Oxidizer.
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純化方法
Purify it by recrystallisation from hot water (solubility of AgNO3 in water is 992g/100mL at 100o and 122g/100mL at 0o). It has also been purified by crystallisation from hot conductivity water by slow addition of freshly distilled EtOH. CAUTION: avoid using EtOH for washing the precipitate; and avoid concentrating the filtrate to obtain further crops of AgNO3 owing to the risk of EXPLOSION (as has been reported to us) caused by the presence of silver fulminate. When using EtOH in the purification, the apparatus should be enveloped in a strong protective shield. [Tully, News Ed (Am Chem Soc) 19 3092 1941; Garin & Henderson J Chem Educ 47 741 1970, Bretherick, Handbook of Reactive Chemical Hazards 4th edn, Butterworths, London, 1985, pp 13-14.] Before being used as a standard in volumetric analysis, analytical reagent grade AgNO3 should be finely powdered, dried at 120o for 2hours, then cooled in a desiccator. Recovery of silver residues as AgNO3 [use protective shield during the whole of this procedure] can be achieved by washing with hot water and adding 16M HNO3 to dissolve the solid. Filter this through glass wool and concentrate the filtrate on a steam bath until precipitation commences. Cool the solution in an ice-bath and filter the precipitated AgNO3. Dry it at 120o for 2hours, then cool it in a desiccator in a vacuum. Store it over P2O5 in a vacuum in the dark. AVOID contact with hands due to formation of black stains.
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不和合性
A strong oxidizer. Reacts violently with combustible and reducing materials. Reacts with acetylene forming a shock-sensitive explosive. Reacts with alkalis, antimony salts; ammonia, arsenites, bromides, carbonates, chlorides, iodides, hydrogen peroxide; thiocyanates, ferrous salts; oils, hypophosphites, morphine salts; creosote, phosphates, tannic acid; tartarates, halides, vegetable extracts, and others. Attacks some forms of plastics, rubber, and coatings.
