Dinitrogen tetroxide, N₂O₄, exists as a planar dimer formed from two NO₂ units.
(a) Lewis electron-dot diagram(s)
(b) Formal charge, regions of electron density, and shape for each N
(c) Hybridization of each N and its relation to geometry
(d) Explanation of uniform N–O bond lengths
(e) Polarity prediction with justification