text: 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) is isolobal with CH and therefore, [Ru(CO)] and [Mo(CO)] are also isolobal with CH. 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) is isolobal with CH, [Re(CO)] is isolobal with .