複選題32. Which of the following statements correctly describe the 18-electron rule and its application to organometallic complexes? (A) The 18-electron rule applies equally well to both main-group compounds and transition-metal complexes (B) Complexes that follow the 18-electron rule are typically low-spin and diamagnetic (C) In square-planar $\mathrm{d}^8$ complexes such as $[\mathrm{PtCl}_4]^{2-}$, the metal center satisfies the 18-electron rule (D) $\pi$-acceptor ligands such as CO contribute two electrons per ligand to the metal center (E) The 18-electron rule predicts stability when the metal center achieves a noble-gas-like configuration with 18 valence electrons