Isoelectronicity

Isoelectronicity is a property of chemical species, which includes atoms, molecules, and ions. Two molecular entities are isoelectronic if they have the same number of valence electrons and the same structure of chemical bonds, even if the chemical elements involved are different.

The word isoelectronic comes from the prefix iso-, meaning "same".

 Examples 
Chemical elements that share a group in the periodic table are isoelectronic. Metallic beryllium, magnesium, calcium, and strontium all have two valence electrons.

Many main group elements form ions that are isoelectronic to noble gases. The sodium cation  and fluorine anion  are both isoelectronic to neon.

Carbon monoxide  and nitrogen  are isoelectronic because each atom has a lone pair and a triple bond. They are also isoelectronic to the nitrosonium cation  and cyanide anion .

Ethenone  is isoelectronic with , a tautomer of diazomethane. Diazomethane's other tautomer, , is isoelectronic with cyanamide, .

Acetone  and azomethane  are not isoelectronic. Although they have the same number of valence electrons, the structure of their chemical bonds is different.

 Sources 

Category:Chemistry