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Completed formatting of chemical formulæ
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andselisk ♦
andselisk ♦
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I think this property has to do with the ease with which Cobaltcobalt makes complexes with NH3$\ce{NH3}$ and amines. The variety and the stability of the complexes containing $\ce{Co^3+}$, surrounded by NH3,$\ce{NH3},$ ethylenediamine, H2O,$\ce{H2O},$ and/or Cl,$\ce{Cl},$ is unparalleled. Iron Fe$\ce{Fe}$ does not make complexes with NH3 in$\ce{NH3}$ under usual conditions. Nickel, Coppercopper and Zinczinc do make one or two complexes with NH3,$\ce{NH3},$ but they are easily destroyed in acidic conditions. The variety and the stability of the Cobaltcobalt complexes is unequalledunequaled.

The stability of the Cobaltcobalt complexes is related to its electronic structure. The Cobaltcobalt atom is Argonargon + 9 electrons. $\ce{Co^3+}$ is Argonargon + 6 electrons. 12 electrons are missing in $\ce{Co^3+}$ and needed to build up the electronic configuration of the next noble gas, Kryptonkrypton. If the $\ce{Co^3+}$ ion is surrounded by 6 ligands like NH3, Cl-$\ce{NH3},$ $\ce{Cl-}$ and H2O,$\ce{H2O},$ it "achieves its goal" of looking like a noble gas.

Cobalt may react with Nitrogennitrogen to produce CoN$\ce{CoN}$ made of $\ce{Co^3+}$ and $\ce{N^3-}$. And maybe this compound CoN$\ce{CoN}$ is surrounded by 6 N2six $\ce{N2}$ in the same way as $\ce{Co^3+}$ is surrounded by 6six ligands in the $\ce{Co^3+}$ complexes. This should be checked by X-ray analysis.

I think this property has to do with the ease with which Cobalt makes complexes with NH3 and amines. The variety and the stability of the complexes containing $\ce{Co^3+}$, surrounded by NH3, ethylenediamine, H2O, and/or Cl, is unparalleled. Iron Fe does not make complexes with NH3 in usual conditions. Nickel, Copper and Zinc do make one or two complexes with NH3, but they are easily destroyed in acidic conditions. The variety and the stability of the Cobalt complexes is unequalled.

The stability of the Cobalt complexes is related to its electronic structure. The Cobalt atom is Argon + 9 electrons. $\ce{Co^3+}$ is Argon + 6 electrons. 12 electrons are missing in $\ce{Co^3+}$ and needed to build up the electronic configuration of the next noble gas, Krypton. If the $\ce{Co^3+}$ ion is surrounded by 6 ligands like NH3, Cl- and H2O, it "achieves its goal" of looking like a noble gas.

Cobalt may react with Nitrogen to produce CoN made of $\ce{Co^3+}$ and $\ce{N^3-}$. And maybe this compound CoN is surrounded by 6 N2 in the same way as $\ce{Co^3+}$ is surrounded by 6 ligands in the $\ce{Co^3+}$ complexes. This should be checked by X-ray analysis.

I think this property has to do with the ease with which cobalt makes complexes with $\ce{NH3}$ and amines. The variety and the stability of the complexes containing $\ce{Co^3+}$, surrounded by $\ce{NH3},$ ethylenediamine, $\ce{H2O},$ and/or $\ce{Cl},$ is unparalleled. Iron $\ce{Fe}$ does not make complexes with $\ce{NH3}$ under usual conditions. Nickel, copper and zinc do make one or two complexes with $\ce{NH3},$ but they are easily destroyed in acidic conditions. The variety and the stability of the cobalt complexes is unequaled.

The stability of the cobalt complexes is related to its electronic structure. The cobalt atom is argon + 9 electrons. $\ce{Co^3+}$ is argon + 6 electrons. 12 electrons are missing in $\ce{Co^3+}$ and needed to build up the electronic configuration of the next noble gas, krypton. If the $\ce{Co^3+}$ ion is surrounded by 6 ligands like $\ce{NH3},$ $\ce{Cl-}$ and $\ce{H2O},$ it "achieves its goal" of looking like a noble gas.

Cobalt may react with nitrogen to produce $\ce{CoN}$ made of $\ce{Co^3+}$ and $\ce{N^3-}$. And maybe this compound $\ce{CoN}$ is surrounded by six $\ce{N2}$ in the same way as $\ce{Co^3+}$ is surrounded by six ligands in the $\ce{Co^3+}$ complexes. This should be checked by X-ray analysis.

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Maurice
Maurice
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I think this property has to do with the ease with which Cobalt makes complexes with NH3 and amines. The variety and the stability of the complexes containing $\ce{Co^3+}$, surrounded by NH3, ethylenediamine, H2O, and/or Cl, is unparalleled. Iron Fe does not make complexes with NH3 in usual conditions. Nickel, Copper and Zinc do make one or two complexes with NH3, but they are easily destroyed in acidic conditions. The variety and the stability of the Cobalt complexes is unequalled.

The stability of the Cobalt complexes is related to its electronic structure. The Cobalt atom is Argon + 9 electrons. $\ce{Co^3+}$ is Argon + 6 electrons. 12 electrons are missing in $\ce{Co^3+}$ and needed to build up the electronic configuration of the next noble gas, Krypton. If the $\ce{Co^3+}$ ion is surrounded by 6 ligands like NH3, Cl- and H2O, it "achieves its goal" of looking like a noble gas.

Cobalt may react with Nitrogen to produce CoN made of $\ce{Co^3+}$ and $\ce{N^3-}$. And maybe this compound CoN is surrounded by 6 N2 in the same way as $\ce{Co^3+}$ is surrounded by 6 ligands in the $\ce{Co^3+}$ complexes. This should be checked by X-ray analysis.