硝酸マグネシウム·6水和物

外観

銀灰色の削り状

定義

本品は、粉末のマグネシウムからなる無機金属である。

溶解性

塩酸及び硫酸には水素を発生して溶け、硝酸には窒素酸化物を発生して溶ける。

解説

マグネシウム，原子番号12の元素．電子配置1s22s22p63s2の周期表2族元素．原子量24.305．3種類の安定同位体(24Mg，25Mg，26Mg)と3種類の放射性同位体が存在する．水銀とアマルガムをつくり多くの金属と合金をつくる．エーテル中で有機ハロゲン化合物RXと化合しグリニャール試薬RMgXを生じる．イオンはEDTA滴定により容量分析ができる．フラッシュランプ，ゲッター，保温材，ベリリウムやチタンなど多くの純金属製造用還元剤などに用いられる．アルミニウムより軽く，アルミニウム，その他との合金は自動車，航空機，ミサイルなどに用いられる．

主な性質

1. 単体マグネシウムは銀白色の金属で、表面にできる酸化物が比較的丈夫なので、通常は金属として使用
2. マグネシウムはアルミニウムより軽い（実用金属の中でも最も軽い。軽量化用途に鋳造、鍛造、延展材として使用される）
3. マグネシウムは、反応性に富む金属で、空気中では酸化皮膜を作り、微粉末を加熱すると、白色閃光を放って燃える（水中で加熱すると、水と反応して水酸化マグネシウムと水素ガスを生成する）
4. マグネシウムは塩素イオン、酸、塩類に対しては耐食性がよくないが、大部分のアルカリ及び有機加合物には耐える
5. マグネシウムはアルミニウムの強度向上や耐食性改善のための添加剤として利用
6. マグネシウムは活性なので、Ｔｉ、Ｚｒ、Ｖ、Ｂ、Ｂｅ等の精錬で還元剤として使われる
7. 海水からマグネシウム塩を多量に含む苦い塩類混合物の粉〔にがり〕が出来る。（「にがり」は、豆乳を凝固させる豆腐製造に使われる）

用途

グリニャール試薬調製用。

用途

還元剤。有機合成(和光試薬時報Vol.66 No.2,p.21(1998))。

用途

高純度金属、還元剤、合金材料。

用途

合金材料、試薬(還元剤)。

用途

試薬(還元剤)。有機合成(和光試薬時報Vol.66 No.2,p.21(1998))。

用途

アルミニウム合金添加用、ジルコニウム?チタニウム製錬用、ノジュラー鋳鉄用、マグネシウム鋳物製造用、防食用、還元剤、マグネシウム電池、化学薬品製造用(グリニヤール試薬、その他)、鉄鋼の脱硫剤

存在

天然に遊離状態では産出しないが、地球上に広く多量に分布している。菱苦土(りょうくど)石、カーナル石、苦灰石（ドロマイト）、滑石、蛇紋(じゃもん)石、石綿などが主要な鉱石であるが、輝石、角閃(かくせん)石などにも含まれる。また可溶性塩類として海水、鉱泉などにも存在している。海水からの効率的・経済的な抽出法が考案されたことにより、マグネシウムの供給は事実上無限と考えられる。また、植物の葉緑素の中にはクロロフィルとして含まれ、動物の生理にも重要な役割を果たしている。

製法

工業的には無水塩化マグネシウムの融解塩電解法と、炭素による高温還元あるいはカーバイド、フェロシリコンなどによる還元法がある。無水塩化マグネシウムは、カーナル石、にがりあるいは海水から直接とるが、酸化マグネシウムを塩素化してつくることもある。また、クロール法によるチタン製造の際の副生塩化マグネシウムも使われる。電解浴はMgCl2・NaCl・KClあるいはMgCl2・2NaClなどの形で660～750℃で電解する。電解槽は鉄または耐火れんが張りで、陽極は黒鉛、陰極は鉄製である。

フェロシリコンによる還元法は、発明者の名にちなんでピジョン法とよばれている。ドロマイトMgCO3・CaCO3を焼成したものに75％ケイ素のフェロシリコン（ケイ素鉄）を加えてブリケット（団鉱）とし、耐熱鋼のレトルトの中に入れて1200℃で熱還元する。これを水銀柱0.001ミリメートル程度の真空で蒸留し、マグネシウムを留出させる。この方法で純度99.7％程度のものが得られる。

炭素による還元は1900～2400℃で行い、生成したマグネシウム蒸気と一酸化炭素を大量の水素ガスで急冷し、得られたマグネシウム粉末を蒸留し、融解してインゴットとする（純度約90％）。この方法は操作が危険で純度もあまりよくないので、現在ではほとんど行われていない。

電解マグネシウムの純度は99.90～99.97％程度で、不純物は銅、マンガン、鉄、ケイ素、鉛などである。これらを除去するため、比較的低温で真空蒸留すると99.99％の製品が得られる。

化粧品の成分用途

還元剤

主な用途

1. アルミニウム合金添加成分（5000系アルミニウム合金、船舶、アルミ缶）
2. 四塩化チタン還元剤（スポンジチタン）
3. 鉄鋼脱硫剤（鋳鉄用）
4. 工具部品（電動工具／ダイカスト）
5. 電子機器部品（パソコン、携帯電話の筐体、磁気ディスク、ロボット）
6. 自動車部品（ホイール）
7. 航空機部品（ミッションケース、鋳物、ヘリコプター）
8. その他（スポーツレジャー、事務機器、触媒）

使用上の注意

強熱すると強い光を放って燃焼する。

説明

Magnesium is a Group 2 element (Group IIA in older labeling schemes). This element has the symbol Mg, atomic number 12, atomic weight of 24.305 g/mol and common oxidation number ＋2. It is the eighth most abundant element in the earth s crust by mass, although ninth in the Universe as a whole. This preponderance of magnesium in the Universe is related to the fact that it is easily built up in supernova stars from a sequential addition of three helium nuclei to carbon (which in turn is made from three helium nuclei). Magnesium constitutes about 2% of the Earth s crust by mass, which makes it the eighth most abundant element in the crust. Magnesium ion’s high solubility in water helps to ensure that it is the third most abundant element dissolved in seawater.

化学的特性

Magnesium is a light, silvery-white metal in various forms, and is a fire hazard.

物理的性質

Magnesium is a lightweight, silvery-white, malleable alkali earth metal that is flammable.It has a weak electronegativity (–1.31), which means it is highly reactive as it combines withsome nonmetals. As with other alkali earth metals, magnesium is a good conductor of heatand electricity. Its melting point is 648.8°C, its boiling point is 1090°C, and its density is1.74 g/cm³, making it about one-fifth the density of iron and only two-thirds as dense asaluminum.

同位体

There are 15 isotopes of magnesium, ranging from Mg-20 to Mg-34. Threeof these isotopes are stable: Mg-24 makes up 78.99% of all magnesium found in theEarth’s crust. Mg-25 makes up 10%, and Mg-26 constitutes most of the rest at 11%.The other 12 isotopes are radioactive and are produced artificially with half-lives rangingfrom microseconds to a few hours.

名前の由来

Magnesium is named after Magnesia, an ancient region of Thessaly, Greece, where it was mined. Magnesium is often confused with another element, manganese. One way to eliminate the confusion is to think of magnesium (Mg) as “12” and manganese (Mn) as “25” and to use the mental trick of remembering that “g” comes before “n” in the alphabet, so magnesium is the one with lower atomic number.

天然物の起源

Magnesium is the eighth most abundant of the elements found in the entire universe, andthe seventh most abundant found in the Earth’s crust. Its oxide (MgO) is second in abundance to oxide of silicon (SiO₂), which is the most abundant oxide found in the Earth’s crust.Magnesium is found in great quantities in seawater and brines, which provide an endless supply. Each cubic mile of seawater contains about 12 billion pounds of magnesium. Althoughmagnesium metal cannot be extracted from seawater directly, it can be extracted by severalchemical processes through which magnesium chloride (MgCl₂) is produced. Electrolysis isthen used with the magnesium chloride as the electrolyte at 714°C to produce metallic magnesium and chlorine gas. Another method of securing magnesium is known as the Pigeonprocess. This procedure uses the magnesium minerals dolomite or ferrosilicon. Dolomite(CaCO₃), which also contains MgCO₃, is crushed and then heated to produce oxides of Caand Mg. The oxides are heated to about 1200°C along with the ferrosilicon (an alloy of ironand silicon), and the silicon reduces the magnesium, producing a vapor of metallic magnesiumthat, as it cools, condenses to pure magnesium metal.

特性

While in a thin solid form, magnesium ignites at 650°C, and it is more easily ignited ina fine powder form. Burning magnesium produces a brilliant white light. It is also used asan oxidizer to displace several other metals from their compound minerals, salts, and ores. Itis alloyed with other metals to make them lighter and more machinable, so that they can berolled, pounded, formed into wires, and worked on a lathe.The ground water in many regions of the United States contains relatively high percentagesof magnesium, as well as some other minerals. A small amount improves the taste of water,but larger amounts result in “hard” water, which interferes with the chemical and physicalaction of soaps and detergents. The result is a scum-like precipitate that interferes with thecleansing action. The solution is the use of water softeners that treat hard water with eithersodium chloride or potassium chloride, which displace the magnesium—making the water“soft,” resulting in a more effective cleansing action.

使用

magnesium plays an important role in various processes within the skin, including amino acid synthesis and protein synthesis (e.g., collagen), and in the metabolism of calcium, sodium, and phosphorus.

定義

Metallic element of atomic number 12, group IIA of the periodic table, aw 24.305, valence = 2; three isotopes. Magnesium is the central element of the chlorophyll molecule; it is also an important component of red blood corpuscles.

一般的な説明

A light silvery metal. The more finely divided material reacts with water to liberate hydrogen, a flammable gas, though this reaction is not as vigorous as that of sodium or lithium with water. In finely divided forms is easily ignited. Burns with an intense white flame. Can be wax coated to render magnesium as nonreactive.

空気と水の反応

Pyrophoric in dust form [Bretherick 1979, p. 104]. Magnesium ribbon and fine magnesium shavings can be ignited at air temperatures of about 950°F and very finely divided powder has been ignited at air temperatures below 900°F. [Magnesium Standard 1967 p. 4]. The more finely divided material reacts with water to liberate hydrogen, a flammable gas, though this reaction is not as vigorous as that of sodium or lithium

反応プロフィール

Magnesium slowly oxidizes in moist air. Reacts very slowly with water at ordinary temperatures, less slowly at 100°C. Reacts with aqueous solutions of dilute acids with liberation of hydrogen [Merck 11th ed. 1989]. In the presence of carbon, the combination of chlorine trifluoride with aluminum, copper, lead, magnesium, silver, tin, or zinc results in a violent reaction [Mellor 2, Supp. 1. 1956]. A mixture of powdered magnesium with trichloroethylene or with carbon tetrachloride will flash or spark under heavy impact [ASESB Pot. Incid, 39. 1968]. Stannic oxide, heated with magnesium explodes [Mellor 7:401. 1946-47]. When carbon dioxide gas is passed over a mixture of powdered magnesium and sodium peroxide, the mixture exploded [Mellor 2:490. 1946-47]. Powdered magnesium plus potassium (or sodium) perchlorate is a friction- sensitive mixture [Safety Eng. Reports. 1947]. An explosion occurred during heating of a mixture of potassium chlorate and magnesium [Chem. Eng. News 14:451. 1936]. Powdered magnesium can decompose performic acid violently [Berichte 48:1139. 1915]. A mixture of finely divided magnesium and nitric acid is explosive [Pieters 1957. p. 28]. Magnesium exposed to moist fluorine or chlorine is spontaneously flammable [Mellor 4:267. 1946-47].

危険性

Magnesium metal, particularly in the form of powder or small particles, can be ignited atrelatively low temperatures. The resulting fires are difficult to extinguish, requiring dry sandor dirt. Water will just accelerate the fire as hydrogen that will intensify the fire is releasedfrom the water.
Some magnesium compounds, whose molecules contain several atoms of oxygen—Mg(ClO₄), for example—are extremely explosive when in contact with moist organic substance,such as your hands.
Although traces of magnesium are required for good nutrition and health, some compoundsof magnesium are poisonous when ingested.

健康ハザード

Inhalation of magnesium dust can produceirritation of the eyes and mucous membranes.Magnesium may react with waterin the bronchial passage to form magnesiumhydroxide, which is caustic and maycause adverse effects on lungs. The fumescan cause metal fever.

火災危険

Behavior in Fire: Forms dense white smoke. Flame is very bright.

職業ばく露

Magnesium alloyed with manganese, aluminum, thorium, zinc, cerium, and zirconium, is used in aircraft, ships, automobiles, hand tools, etc., because of its lightness. Dow metal is the general name for a large group of alloys containing over 85% magnesium. Magnesium wire and ribbon are used for degassing valves in the radio industry and in various heating appliances; as a deoxidizer and desulfurizer in copper, brass, and nickel alloys; in chemical reagents; as the powder in the manufacture of flares, incendiary bombs, tracer bullets, and flashlight powders; in the nuclear energy process; and in a cement of magnesium oxide and magnesium chloride for floors. Magnesium is an essential element in human and animal nutrition and also in plants, where it is a component of altypes of chlorophyll. It is the most abundant intracellular divalent cation in both plants and animals. It is an activator of many mammalian enzymes

特性

比重がアルミの 2/3 と実 用金属中で最も軽い 

重量当たりの強度や曲げ 弾性率が高い 

電気・熱の伝導性が高い

発がん性

MgO is regarded as an “experimental tumorigen”, although the only reference in the literature that could be found relating to the carcinogenicity of MgO was an instillation study, in which MgO dust instilled intratracheally for 30 weeks resulted in induction of histiocytic lymphomas in hamsters. It was also demonstrated that MgO enhanced the tumorigenesis of benzo[a]pyrene and was an effective carrier agent for the experimental induction of respiratory tract tumors.

環境運命予測

Aquatic fate: Because of magnesium ion’s high solubility in water, it is the third most abundant element dissolved in seawater, because rainwater falling on rocks can also increase the level of magnesium in river and seawater.

輸送方法

UN1869 Magnesium pellets, turnings or ribbons, Hazard Class: 4.1; Labels: 4.1-Flammable solid. UN1418 Magnesium, powder or Magnesium alloys, powder, Hazard Class: 4.3; Labels: 4.3-Dangerous when wet material, 4.2-Spontaneously combustible material. UN2950 Magnesium granules, coated, particle size not <149 μm, Hazard Class: 4.3; Labels: 4.3-Dangerous when wet material

純化方法

It slowly oxidises in moist air and tarnishes. If dark in colour, do not use. The shiny solid should be degreased by washing with dry Et2O, dry it in vacuo and keep it in a N2 atmosphere. It can be activated by stirring it in Et2O containing a crystal of I2 then filtering it off, before drying and storing. [Gmelin’s Magnesium (8th edn) 27A 121 1937.]

不和合性

Dust may form explosive mixture with air. Capable of self-ignition in moist air. The substance is a strong reducing agent. Reacts violently with, oxidizers, strong acids; acetylene, ammonium salts; arsenic, beryllium fluoride, carbon tetrachloride, carbonates, chloroform, cyanides, chlorinated hydrocarbons; ethylene oxide; hydrocarbons, metal oxides; methanol, phosphates, silver nitrate; sodium peroxide; sulfates, trichloroethylene, and many other substances, causing fire and explosion hazards. Finely divided material, in powdered, chip or sheet form, reacts with moisture or acids, evolving flammable hydrogen gas, causing fire and explosion hazard. Finely divided form is readily ignited by a spark or flame. It splatters and burns at above 1260℃