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ChemDoc (154)
A specific sub-type of covalent bond in which the bonding electrons between atoms are shared UNEQUALLY. This can only be the case when two atoms are non-equivalent in electronegativity, which governs how "electrophilic" (electron-loving) an atom is. Halogens such as Fluorine are high electronegative, and metalloids such as silicon are not. Ergo, a flourine-silicon bond would be highly polar.