Lewis acids and bases ionic bonding. Classically, the term "Lewis acid" is restricted to trigonal planar species with an empty p orbital, such as BR where R can be an organic substituent or a halide. For the purposes of discussion, even complex compounds such as EtAlCl and AlCl are treated as trigonal planar Lewis acids. Metal ions such as Na, Mg, and Ce, which are invariably complexed with additional ligands, are often sources of coordinatively unsaturated derivatives that form Lewis adducts upon reaction with a Lewis base[citation needed]. Other reactions might simply be referred to as "acid-catalyzed" reactions. Some compounds, such as HO, are
Magic Tree House Magic Tree House Merlin Mission Books 1-27 were written for more advanced readers. They are more challenging adventures for readers ages 7–10. The Magic Tree House Merlin Missions were originally ordered sequentially, starting at Book #29 (Christmas in Camelot). With the 25th anniversary re-prints, the books have been separated into their own distinct series and re-numbered starting at Merlin Mission #1. On January 6, 2015, the first Magic Tree House Super Edition was released. It is 183 pages long. The super editions are longer than the original Magic Tree House books and the Magic Tree House Merlin Missions. The Magic