Lead oxide - Sankanari (English spelling)

Compounds of lead and oxygen. The following are well known, but others include Pb ₂ O ₃ , Pb ₁₂ O ₁₇ , and Pb ₁₂ O ₁₉ .

(1) Lead(II) oxide (lead monoxide) A low-temperature type is naturally produced as masicotte. It has been used as a pigment since ancient times. There are two types: a yellow, orthorhombic, high-temperature stable type (β (beta) type) and an orange-red, tetragonal, low-temperature stable type (α (alpha) type). When the α type is heated to 488°C, it becomes the β type. The α type is also called mitsuda, and the β type is called gin mitsuda. When air is blown into molten lead, or lead carbonate _PbCO3 or lead nitrate Pb( _NO3 ) ₂ is heated in air, the yellow powder obtained is cooled to obtain an orange-red product, which is generally called litharge or mitsudaso. It is an amphoteric oxide that dissolves in acid to become lead(II) salt, and in alkali to become _{zincate M2PbO2} . Used in the manufacture of vinyl chloride stabilizers, pesticides (lead arsenate), paints, optical glass, storage batteries, and red lead. Toxic.

(2) Lead(IV) oxide (lead dioxide) It is prepared by melting and oxidizing lead(II) oxide with sodium chlorate, or by oxidizing an alkaline solution of lead(II) salt with hypochlorite. It is a brown powder. At 290°C, it decomposes into dilead trioxide Pb ₂ O ₃ (PbO・PbO ₂ ) and oxygen, and at 370°C, it becomes trilead tetroxide Pb ₃ O ₄ . It is a strong oxidizing agent, and when heated with concentrated hydrochloric acid, it produces chlorine gas. It has been called lead peroxide, but since it has a rutile crystal structure, it is not a peroxide (containing O--O bonds), so lead peroxide is a misnomer. It dissolves in concentrated alkaline hydroxide solution to become lead(IV) salt. It is used as an oxidizing agent in organic synthesis, in batteries, fireworks, and as a hardener for polysulfides.

(3) Lead(IV) oxide, lead(II) The chemical formula is Pb ₃ O ₄ . Pb and Pb coexist as Pb ₂ PbO ₄ . The specific gravity of the red crystal is 9.07. It is also called trilead tetroxide, red lead oxide, red lead, and red gourd.

[Kenichi Morinaga and Katsunori Nakahara]

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

鉛と酸素の化合物。次のものがよく知られているが、その他にもPb₂O₃、Pb₁₂O₁₇、Pb₁₂O₁₉なども存在する。

(1)酸化鉛(Ⅱ)（一酸化鉛）　天然にマシコットとして低温型が産する。古くから顔料などとして用いられていた。黄色、斜方晶系の高温安定型（β(ベータ)型）と、橙赤(とうせき)色、正方晶系の低温安定型（α(アルファ)型）の2種がある。α型を488℃に熱するとβ型となる。α型を金密陀(みつだ)、β型を銀密陀ともいう。融解した鉛に空気を吹き込んだり、炭酸鉛PbCO₃または硝酸鉛Pb(NO₃)₂などを空気中で加熱して得られる黄色粉末を冷却すると、橙赤色のものが得られ、一般にリサージあるいは密陀僧とよばれる。両性酸化物で、酸に溶けて鉛(Ⅱ)塩、アルカリに溶けて亜鉛(あなまり)酸塩M₂PbO₂となる。塩化ビニル安定剤、農薬（ヒ酸鉛）、塗料、光学ガラス、蓄電池、鉛丹(えんたん)の製造に用いられる。有毒。

(2)酸化鉛(Ⅳ)（二酸化鉛）　酸化鉛(Ⅱ)を塩素酸ナトリウムと融解酸化するか、鉛(Ⅱ)塩のアルカリ性溶液を次亜塩素酸塩で酸化してつくる。褐色の粉末。290℃で三酸化二鉛Pb₂O₃(PbO・PbO₂)と酸素に分解し、370℃で四酸化三鉛Pb₃O₄となる。強い酸化剤で、濃塩酸と温めると塩素ガスを発生する。過酸化鉛とよばれたことがあるが、ルチル型の結晶構造をもつので過酸化物（O-O結合を含む）ではなく過酸化鉛は誤称である。濃水酸化アルカリ溶液に溶けて鉛(Ⅳ)酸塩となる。有機合成での酸化剤、電池、花火、ポリ硫化物の硬化剤に用いる。

(3)酸化鉛(Ⅳ)鉛(Ⅱ)　化学式Pb₃O₄。PbとPbの共存するPb₂PbO₄である。赤色結晶の比重は9.07。四酸化三鉛、赤色酸化鉛、鉛丹、光明丹(こうみょうたん)ともよばれる。

［守永健一・中原勝儼］

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