The case of the linear I7 3-chain (Figure ) is similar to that of the I8 2-chain, with the chain needing to bend around its central atom to achieve 2n electrons for n bonds. Its detailed discussion would not add much to the above-exposed arguments. The impossibility of forming ERMBs of more than 3 centers results in the formation of a weak [I•I2•I•I2•I] 3-formal complex as shown in the bottom of Figure .