Pi backbonding

<p>In <a href="/facts/Chemistry/SrNqkGVm">chemistry</a>, pi backbonding or π backbonding is a <a href="/facts/Pi_bond/3Q6LAGYK">π-bonding</a> interaction between a filled (or half filled) <a href="/facts/Atomic_orbital/tKhgl6mL">orbital</a> of a transition metal atom and a vacant <a href="/facts/Atomic_orbital/tKhgl6mL">orbital</a> on an adjacent ion or molecule. In this type of interaction, electrons from the metal are used to bond to the <a href="/facts/Ligand/6etB3qeW">ligand</a>, which dissipates excess negative <a href="/facts/Electric_charge/xxsBfmlB">charge</a> and stabilizes the metal. It is common in <a href="/facts/Transition_metal/0slGWoLQ">transition metals</a> with low oxidation states that have ligands such as <a href="/facts/Metal_carbonyl/KzJBcMzU">carbon monoxide</a>, <a href="/facts/Olefins/RtYcS6kU">olefins</a>, or <a href="/facts/Phosphine/aYysn5TS">phosphines</a>. The <a href="/facts/Ligand/6etB3qeW">ligands</a> involved in π backbonding can be broken into three groups: <a href="/facts/Metal_carbonyl/KzJBcMzU">carbonyls</a> and nitrogen analogs, <a href="/facts/Alkene/RtYcS6kU">alkenes</a> and <a href="/facts/Alkyne/VHI4N5Wo">alkynes</a>, and <a href="/facts/Phosphines/aYysn5TS">phosphines</a>. Compounds where π backbonding is prominent include <a href="/facts/Nickel_carbonyl/8Py5Dre1">Ni(CO)4</a>, <a href="/facts/Zeise%2527s_salt/DWyXJEh0">Zeise's salt</a>, and <a href="/facts/Abiological_nitrogen_fixation_using_homogeneous_catalysts/m8q36uBL">molybdenum and iron dinitrogen complexes</a>.
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Pi backbonding open-in-new

Pi backbonding