قاعدة نيتروجينية: الفرق بين النسختين

▲Nitrogenous bases are typically classified as the derivatives of two parent compounds, [[pyrimidine]] and [[purine]].<ref>Nelson and Cox 2008, p. 272.</ref> They are [[non-polar]] and due to their [[aromaticity]], [[trigonal planar molecular geometry|planar]]. Both pyrimidines and purines resemble [[pyridine]] and are thus weak bases and relatively unreactive towards [[electrophilic aromatic substitution]].<ref>Carey 2006, p. 1206.</ref>