The present issue of Structure and Bonding is dedicated to applied group 13 chemistry, particularly for the elements boron and aluminum, and to a lesser degree gallium and indium. Although boron is a trace element (0.01 g kg 1) in the earth's crust, it has been concentrated in a few locations by geochemical processes and is relatively easy to mine as borax. Aluminum, on the other hand, is the most abundant metal in the earth's crust (82 g kg 1) and dispersed widely throughout the globe. Thus, boron and aluminum are readily available and their associated products or compounds are usually...