Chemical bond

A chemical bond is the association of <a href="/facts/Atom/69syB8dH">atoms</a> or <a href="/facts/Ion/wrbwhF3z">ions</a> to form <a href="/facts/Molecule/N9ljSfFq">molecules</a>, <a href="/facts/Crystal/e2R2mk3E">crystals</a>, and other structures. The bond may result from the <a href="/facts/Coulomb%2527s_law/V0lR5NKv">electrostatic force</a> between oppositely charged ions as in <a href="/facts/Ionic_bonding/R6nUJI5u">ionic bonds</a> or through the sharing of electrons as in <a href="/facts/Covalent_bond/EzMLf3Pz">covalent bonds</a>, or some combination of these effects. Chemical bonds are described as having different strengths: there are "strong bonds" or "primary bonds" such as <a href="/facts/Covalent_bond/EzMLf3Pz">covalent</a>, <a href="/facts/Ionic_bond/R6nUJI5u">ionic</a> and <a href="/facts/Metallic_bonding/Ht958du4">metallic</a> bonds, and "weak bonds" or "secondary bonds" such as <a href="/facts/Dipole%25E2%2580%2593dipole_interaction/xIcFMvL7">dipole–dipole interactions</a>, the <a href="/facts/London_dispersion_force/zU842d26">London dispersion force</a>, and <a href="/facts/Hydrogen_bond/85V86IIg">hydrogen bonding</a>. 
Since opposite <a href="/facts/Electric_charge/xxsBfmlB">electric charges</a> attract, the negatively charged <a href="/facts/Electron/L0KBo5cW">electrons</a> surrounding the nucleus and the positively charged <a href="/facts/Proton/clCjepXP">protons</a> within a <a href="/facts/Atomic_nucleus/orpIm5Xl">nucleus</a> attract each other. Electrons shared between two <a href="/facts/Atomic_nucleus/orpIm5Xl">nuclei</a> will be attracted to both of them. "Constructive <a href="/facts/Quantum_mechanical/BRc3Mzgr">quantum mechanical</a> <a href="/facts/Wavefunction/KgM5ykjY">wavefunction</a> <a href="/facts/Wave_interference/lI5f78I4">interference</a>" stabilizes the paired nuclei (see Theories of chemical bonding). Bonded nuclei maintain an optimal distance (the bond distance) balancing attractive and repulsive effects explained quantitatively by <a href="/facts/Quantum_mechanics/BRc3Mzgr">quantum theory</a>.
The atoms in <a href="/facts/Molecule/N9ljSfFq">molecules</a>, <a href="/facts/Crystal/e2R2mk3E">crystals</a>, <a href="/facts/Metal/pqQVs8QU">metals</a> and other forms of matter are held together by chemical bonds, which determine the structure and properties of matter.
All bonds can be described by <a href="/facts/Quantum_mechanics/BRc3Mzgr">quantum theory</a>, but, in practice, simplified rules and other theories allow chemists to predict the strength, directionality, and polarity of bonds. The <a href="/facts/Octet_rule/X9jxSsos">octet rule</a> and <a href="/facts/VSEPR_theory/WqsRgVRV">VSEPR theory</a> are examples. More sophisticated theories are <a href="/facts/Valence_bond_theory/F04YPkfJ">valence bond theory</a>, which includes <a href="/facts/Orbital_hybridization/Fl7sz8Jm">orbital hybridization</a> and <a href="/facts/Resonance_(chemistry)/5tymwoIP">resonance</a>, and <a href="/facts/Molecular_orbital_theory/VJ6Kg8bI">molecular orbital theory</a> which includes the <a href="/facts/Linear_combination_of_atomic_orbitals/K7mcdv2L">linear combination of atomic orbitals</a> and <a href="/facts/Ligand_field_theory/QSzm3hg8">ligand field theory</a>. <a href="/facts/Electrostatics/bxkuW6s4">Electrostatics</a> are used to describe bond polarities and the effects they have on chemical substances.

Chemical bond open-in-new

Chemical bond