Oxidation Number - Thank You

Japanese: 酸化数 - サンカスウ

A number that represents the formal oxidation state of an element in a compound. It has also been called the Stock number, but IUPAC has decided that this name should not be used. It is useful when dealing with redox reactions. The definition of an oxidation number is the number of charges remaining on an atom of the element in question when the electron pairs in a bond involving that element are assigned to the more electronegative element. Fractions and non-integers are not allowed. Oxidation numbers are determined by the following rules:
(1) The oxidation number of an atom in an element is 0. For example, the oxidation number of nitrogen in _N2 is 0.
(2) The oxidation number of a monatomic ion in an ionic compound is the valence of that ion.
(3) In polyatomic ions, the sum of the oxidation numbers of each atom should be equal to the valence of the ion.
(4) The oxidation number of hydrogen in a compound is 1, except for metal hydrides, where the oxidation number is -1.
(5) The oxidation number of oxygen in a compound is -2. An exception is _OF2 , where the oxidation number is 2. For peroxides, the oxidation number is -1. The dioxide (superoxide) ion _O2- ^and the trioxide (ozonide) ion _O3- are both considered to be -1 ^and are not considered as fractions.
(6) In all compounds containing fluorine, the oxidation number of fluorine is -1.
The IUPAC Gold Book glossary states that the oxidation number of the central atom of a ligand is the number of charges that the central atom would have if all of the ligands were removed along with the electron pairs they share with the central atom. Oxidation numbers are expressed in Roman numerals, with only the oxidation number of the central atom placed in parentheses after the name of the element in the compound name. Oxidation numbers can be positive or negative integers or zero, but - is used only if the number is negative and + is not used if the number is positive. Since there is no zero in Roman numerals, the Arabic numeral 0 is used. When expressing oxidation numbers in chemical formulas, they are superscripted. Examples include iron pentacarbonyl(0) [Fe ⁰ (CO) ₅ ], iron sulfate(III), ferricyanide ion(II) [Fe ^Ⅱ (CN) ₆ ] ^4- .

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

Japanese:

化合物中の元素の形式的な酸化状態を表す数値．Stock数ともよばれたが，IUPACはこの名称は使うべきでないとしている．酸化還元反応を取り扱うときに便利である．酸化数の定義は，その元素が関与している結合中の電子対を電気的に陰性な元素のほうに割り当てたとき，着目している元素の原子上に残る電荷の数である．ただし分数，非整数は使わない．酸化数は以下の規則で定める．
(1)単体中の原子の酸化数は0．たとえば，N₂ 中の窒素の酸化数は0．
(2)イオン性化合物中の単原子イオンの酸化数は，そのイオンの価数．
(3)多原子分子イオンでは，各原子の酸化数の総和がイオンの価数に等しくなるようにする．
(4)化合物中の水素の酸化数は1，ただし金属水素化物では－1．
(5)化合物中の酸素の酸化数は－2．例外としてOF₂では2．過酸化物では－1．二酸化物(超酸化物)イオン O₂^－，三酸化物(オゾン化物)イオン O₃^－では，まとめて－1として分数にはしない．
(6)フッ素を含むすべての化合物中でフッ素の酸化数は－1．
IUPAC認定用語集Gold Bookは，配位体の中心原子の酸化数は，すべての配位子が中心原子と共有する電子対とともに取り除かれたときに，中心原子が示すと考えられる荷電数としている．酸化数の表記は，化合物名のなかでは中心原子の酸化数のみを元素名の後に(　)に入れて，ローマ数字で示す．酸化数は正または負の整数かゼロであるが，負の場合のみ－をつけ，正のときは＋を使わない．ローマ数字にゼロはないので，アラビア数字の0を用いる．化学式中で酸化数を表示する場合は右肩つきとする．ペンタカルボニル鉄(0)[Fe⁰ (CO)₅]，硫酸鉄(Ⅲ)，ヘキサシアノ鉄(Ⅱ)酸イオン [Fe^Ⅱ(CN)₆]^4－など．