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Speaking: Arrow Symbols in Organic Chemistry* By: Anthony J.
O'Lenick Jr., Siltech LLC; and James Ashenhurst, PhD, Posted:
September 25, 2012 There are eight different types of arrows
encountered in organic chemistry. Here is a little guide to
them. The Forward Arrow This arrow, shown in Figure 1, is
otherwise known as the “reaction arrow.” The purpose of this
arrow is to show action. “BH3, then NaOH/H2O2″ might not seem
like “action,” but alkene's double bond is being ripped asunder
in order to form new bonds to boron and hydrogen. With the
addition of H2O2, the bond to boron is replaced with one to
oxygen. That is a eventful day in the life of an alkene. There
isn’t any hard and fast rule about what is supposed to go above
or below the arrow, although reagents tend to go above and
solvents tend to go below. You’ll often see a sequence of
reactions placed over the arrow and numbered “1) , 2)