Editing Isolobal principle (section)

===Isoelectronic fragments===
The isolobal analogy can also be used with isoelectronic fragments having the same coordination number, which allows charged species to be considered. For example, Re(CO)<sub>5</sub> is isolobal with CH<sub>3</sub> and therefore, [Ru(CO)<sub>5</sub>]<sup>+</sup> and [Mo(CO)<sub>5</sub>]<sup>−</sup> are also isolobal with CH<sub>3</sub>. Any 17-electron metal complex would be isolobal in this example.

In a similar sense, the addition or removal of electrons from two isolobal fragments results in two new isolobal fragments. Since Re(CO)<sub>5</sub> is isolobal with CH<sub>3</sub>, [Re(CO)<sub>5</sub>]<sup>+</sup> is isolobal with {{chem|CH|3|+}}.<ref name=DMA>{{cite book|last1=Douglas |first1=B.|last2=McDaniel |first2=D.|last3=Alexander |first3=J.|edition=3rd|publisher=Wiley & Sons|title=Concepts and Models of Inorganic Chemistry|year=1994}}</ref>