noble gas rule

chemistry

Also known as: 18-electron rule

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July 1, 2026

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The "noble gas rule," also known as the octet rule, describes the tendency of atoms to achieve a stable electron configuration with eight electrons in their outer shell, mirroring that of noble gases. Noble gases themselves are a group of elements (helium, neon, argon, krypton, xenon, radon, and oganesson) known for their extreme stability and low reactivity due to this complete outer electron shell. This stable configuration is the driving force behind chemical bonding, as other elements tend to gain, lose, or share electrons to attain this eight-electron arrangement.1234

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chemical bonding
Organometallic compounds
…empirical rules, among which the 18-electron rule is the analogue of the octet rule of main-group compounds. According to this rule, the most stable organometallic compounds are those having 18 electrons in the valence shell, a term in this context extended to include the outermost d orbitals. Nickel tetracarbonyl, Ni(CO)₄,…
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…empirical rules, among which the 18-electron rule is the analogue of the octet rule of main-group compounds. According to this rule, the most stable organometallic compounds are those having 18 electrons in the valence shell, a term in this context extended to include the outermost d orbitals. Nickel tetracarbonyl, Ni(CO)₄,…
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coordination compound
Geometry
…18-electron rule (sometimes called the noble gas rule), which states that coordination compounds in which the total number of valence electrons approaches but does not exceed 18 (the number of electrons in the valence shells of the noble gases) are most stable. The stabilities of 18-electron valence shells are also…
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…18-electron rule (sometimes called the noble gas rule), which states that coordination compounds in which the total number of valence electrons approaches but does not exceed 18 (the number of electrons in the valence shells of the noble gases) are most stable. The stabilities of 18-electron valence shells are also…
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