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Arrow Pushing Guide

The rules of arrow pushing Interpretation Generic Example Molecular Example

An arrow pointing from a to an means that the bond breaks and a forms on A B A B H Cl H Cl the target atom.

An arrow pointing from a lone pair to an atom means that the lone pair form a new bone to the B A A B Cl H H Cl target atom.

An arrow pointing from a double or to an atom means that one of the bonds break, and those O O electrons form a new lone pair on the target atom. A B A B H H H H

An arrow pointing from a lone pair to a bond means the lone pair electrons are used to increase the bond O O A B order of the target bond (e.g., a single bond becomes A B a ). H H H H

Additional examples

Interpretation Example

The arrow pointing from the bromine lone pair to the methyl group means that those electrons will be used to form a new Br-C bond. Since can only have four bonds, H Br H it must lose a bond in order to form the new Br-C bond. The second arrow, which points O O Br from the O-C bond to , tells us that carbon will lose its bond to oxygen, and H H oxygen will keep those electrons as a lone pair. Therefore, the O-C bond breaks, and a new lone pair is formed on oxygen.

The arrow pointing from the oxygen lone pair to the O-C bond means that the elec- H H H H trons from that lone pair will be used to form a new O-C bond. Since a single bond N N already exists between oxygen and carbon, a double bond will be formed. Since carbon can only form four bonds, carbon must lose a bond in order to form the new bond to O O oxygen. The second arrow, which points from the C-N double bond to , tells us that one of the C-N bonds will break, and the electrons from that bond will form a new lone pair on nitrogen.

The arrow that points from the C-C double bond to the atom means that the H double bond will break (leaving a single bond), and the electrons from that broken H bond will form a new bond between one of the carbon and hydrogen. Since Br hydrogen can only form one bond at a time, it must lose its bond to bromine. The other Br arrow, which points from the H-Br bond to the bottom carbon atom, tells us that the electrons from the broken H-Br bond will be used to form a new bond between bromine and the bottom carbon atom. In order for the bottom carbon atom to form this bond to bromine, it must be true that the top carbon atom is the atom that forms the new bond to hydrogen.

The arrow that points from the oxygen lone pair to the O-S bond means that the lone O pair of electrons on oxygen will be used to form a new O-S bond. The second arrow, O S which points from the other O-S bond to the hydrogen ion, tells us that this O-S bond S H O H will break, and the electrons from it will be used to form a new bond between the O O oxygen and the hydrogen. O H H