Input interpretation
pentamethylcyclopentadienyl anion | structure diagram
Result
Draw the Lewis structure of pentamethylcyclopentadienyl anion. Start by drawing the overall structure of the molecule, ignoring potential double and triple bonds: Count the total valence electrons of the carbon (n_C, val = 4) and hydrogen (n_H, val = 1) atoms, including the net charge: 10 n_C, val + 15 n_H, val - n_charge = 56 Calculate the number of electrons needed to completely fill the valence shells for carbon (n_C, full = 8) and hydrogen (n_H, full = 2): 10 n_C, full + 15 n_H, full = 110 Subtracting these two numbers shows that 110 - 56 = 54 bonding electrons are needed. Each bond has two electrons, so in addition to the 25 bonds already present in the diagram add 2 bonds. To minimize formal charge carbon wants 4 bonds. Identify the atoms that want additional bonds and the number of electrons remaining on each atom. The net charge has been given to the most electronegative atom, carbon: Fill in the 2 bonds by pairing electrons between adjacent highlighted atoms, noting the formal charges of the atoms: Answer: | |