三酸化二鉄

解説Fe2O3(159.69)．酸化鉄(Ⅲ)ともいう．三酸化二鉄は，鉄の酸化物としてはもっとも普通のもの．一般に赤色の粉末だが，製法，処理により黄赤，赤褐色，紫，黒色を呈する．α形とγ形があり，硝酸塩，水酸化物を空気中で焼くとα形が，四酸化三鉄を徐々に酸化するとγ形が得られる．高温ではα形になる．α形は天然には赤鉄鉱として産出する．密度5.12～5.24 g cm－3．融点1550 ℃．モース硬さ5.5～6.5．強熱すると分解してFe3O4になる．水に不溶．酸には徐々に溶けて鉄(Ⅲ)塩になる．湿った空気中では水蒸気を強く吸収する．赤色顔料(べんがら)，磁性材料，触媒，研磨剤に用いられる．森北出版「化学辞典（第2版）

用途磁性材料、塗料

用途顔料、塗料着色剤

用途磁性材料(フェライト及び磁気テープの主原料)、塗料(船底塗料、錆止塗料)、印刷インキ、合成樹脂、建材(セメントかわら、スレート、アスベスト床、壁材の着色顔料)、製紙、陶磁器、道路、ゴム、絵具、クレヨン等の着色料、農薬、化粧品原料(清浄用化粧品、頭髪化粧品、基礎化粧品、メークアップ化粧品、芳香化粧品、日焼け?日焼け止め化粧品、口唇化粧品、口腔化粧品等)、食品添加物(バナナ、コンニャク)

説明Iron oxides are produced synthetically and consist essentially of anhydrous and/or hydrated iron oxides. The range of hues includesyellows, reds, browns and blacks. Food quality iron oxides are primarily distinguished from technical grades by the comparatively low levels of contamination by other metals. This is achieved by the selection and control of the source of iron and/or by the extent of chemical purification during the manufacturing process. Iron oxides have been used to color confectionery, fillings and decorations for pastry products, cheese products, fish paste, pet foods, cosmetics and pharmaceutical products.

天然物の起源Iron(III) oxide occurs in nature as the mineral hematite. It is the principal ore of iron from which the metal and its alloys are produced. Also, this oxide occurs in the mineral, limonite, 2Fe2O33H2O. An important application of this compound involves producing red, orange, and yellow pigments. Other applications are in coatings for metals, steel and rubber; in ceramics; and as a catalyst for oxidation reactions.

使用Ferric Oxide is a nutrient and dietary supplement that is a source of iron.

製造方法Iron(III) oxide is prepared as a reddish-brown hydrated precipitate by treating an aqueous solution of an iron(III) salt with caustic soda: 2FeCl3 + 6NaOH → Fe2O33H2O + 6NaCl It also is obtained by thermal decomposition of iron(II) sulfate or the brown oxide hydroxide: 2FeSO4 → Fe2O3 + SO2 + SO3 2FeO(OH) → Fe2O3 + H2O The oxide is prepared in industrial scale by first precipitating iron(II) hydroxide Fe(OH)2 by treating aqueous solutions of iron(II) sulfate and caustic soda. The Fe(OH)2 is then oxidized to iron(III) hydroxide by aeration. The latter is dehydrated by heating: Fe2+ (aq) + OHˉ (aq) → Fe(OH)2(s) → 2Fe(OH)3 → Fe2O3 + 3H2O It also is produced by ignition of iron(III) oxalate and iron carbonyls: 2Fe2(C2O4)3 +3O2 → 2Fe2O3 + 12CO.