Input interpretation
metaborate anion
Lewis structure
Draw the Lewis structure of metaborate anion. Start by drawing the overall structure of the molecule, ignoring potential double and triple bonds: Count the total valence electrons of the boron (n_B, val = 3) and oxygen (n_O, val = 6) atoms, including the net charge: n_B, val + 2 n_O, val - n_charge = 16 Calculate the number of electrons needed to completely fill the valence shells for boron (n_B, full = 6) and oxygen (n_O, full = 8): n_B, 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 oxygen wants 2 bonds and boron wants 3 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 boron to the other highlighted oxygen atom would result in an equivalent molecule: Answer: | |
General properties
formula | (BO_2^-)_n net ionic charge | -1 alternate names | metaborate | metaborate(1-) | oxido-oxoborane
Other properties
ion class | anions | oxoanions | polymeric ion
Thermodynamic properties
molar free energy of formation Δ_fG° | aqueous | -678.9 kJ/mol (kilojoules per mole) molar heat of formation Δ_fH° | aqueous | -772.4 kJ/mol (kilojoules per mole) molar entropy S° | aqueous | -37.2 J/(mol K) (joules per mole kelvin)