Input interpretation
aluminate anion
Lewis structure
Draw the Lewis structure of aluminate anion. Start by drawing the overall structure of the molecule, ignoring potential double and triple bonds: Count the total valence electrons of the aluminum (n_Al, val = 3) and oxygen (n_O, val = 6) atoms, including the net charge: n_Al, val + 2 n_O, val - n_charge = 16 Calculate the number of electrons needed to completely fill the valence shells for aluminum (n_Al, full = 6) and oxygen (n_O, full = 8): n_Al, full + 2 n_O, full = 22 Subtracting these two numbers shows that 22 - 16 = 6 bonding electrons are needed. Each bond has two electrons, so in addition to the 2 bonds already present in the diagram add 1 bond. To minimize formal charge aluminum wants 3 bonds and oxygen wants 2 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, oxygen: Fill in the 1 bond by pairing electrons between adjacent highlighted atoms, noting the formal charges of the atoms. Double bonding aluminum to the other highlighted oxygen atom would result in an equivalent molecule: Answer: | |
General properties
formula | (AlO_2)^- net ionic charge | -1 alternate names | aluminate | aluminate(1-) | oxido-oxoalumane
Other properties
ion class | anions | oxoanions | polyatomic ions
Thermodynamic properties
molar free energy of formation Δ_fG° | aqueous | -830.9 kJ/mol (kilojoules per mole) molar heat of formation Δ_fH° | aqueous | -930.9 kJ/mol (kilojoules per mole) molar entropy S° | aqueous | -36.8 J/(mol K) (joules per mole kelvin)