定义Definition
官能团是有机分子中决定其主要化学性质的原子或原子团，如碳碳双键、羟基 –OH、羧基 –COOH。含有相同官能团的化合物具有相似的化学反应，构成同一类有机物。
A functional group is the atom or group of atoms in an organic molecule that determines its characteristic chemical reactions, such as the C=C double bond, the hydroxyl group –OH or the carboxyl group –COOH. Compounds with the same functional group react similarly and form one class of organic compound.
常见官能团Common functional groups
碳碳双键 C=C（烯烃）、碳碳三键 C≡C（炔烃）、卤素原子 –X（卤代烃）、羟基 –OH（醇、酚）、醚键 C–O–C（醚）、醛基 –CHO（醛）、羰基 C=O（酮）、羧基 –COOH（羧酸）、酯基 –COO–（酯）、氨基 –NH₂（胺）、酰胺基 –CONH₂（酰胺）、氰基 –C≡N（腈）。
C=C double bond (alkenes), C≡C triple bond (alkynes), halogen –X (halogenoalkanes), hydroxyl –OH (alcohols, phenols), ether link C–O–C (ethers), aldehyde group –CHO (aldehydes), carbonyl C=O (ketones), carboxyl –COOH (carboxylic acids), ester group –COO– (esters), amino –NH₂ (amines), amide –CONH₂ (amides), nitrile –C≡N (nitriles).
同系物Homologous series
官能团相同、组成上相差一个或若干个 CH₂ 的一系列化合物称为同系列，如甲醇、乙醇、丙醇。同系物有相同的通式（醇为 CₙH₂ₙ₊₁OH），化学性质相似，物理性质随碳链增长而规律变化，例如沸点逐渐升高。
A series of compounds with the same functional group, each differing from the next by CH₂, is a homologous series, such as methanol, ethanol and propanol. Members share a general formula (CₙH₂ₙ₊₁OH for alcohols), have similar chemical properties, and show a steady trend in physical properties as the chain lengthens, such as rising boiling points.
在命名中的作用Role in naming
系统命名中，主要官能团决定化合物的类别名和后缀，如 -ol（醇）、-al（醛）、-one（酮）、-oic acid（羧酸）。分子中有多个官能团时，按优先次序选出主官能团作后缀，其余作前缀，例如 2-羟基丙酸（乳酸）中羧基优先，羟基作前缀。
In systematic names the principal functional group sets the class and suffix, such as -ol (alcohol), -al (aldehyde), -one (ketone) and -oic acid (carboxylic acid). When there are several, the senior group becomes the suffix and the others prefixes: in 2-hydroxypropanoic acid (lactic acid) the carboxyl group takes priority and hydroxyl is a prefix.
年表Timeline
- 1832
李比希与维勒提出苯甲酰基在反应中保持不变的“基”理论
Liebig and Wöhler propose the radical theory, with the benzoyl group unchanged through reactions
- 1853
热拉尔提出类型论，按结构类型对有机物分类
Gerhardt proposes type theory, classifying organic compounds by structural type
- 1892
日内瓦会议制定第一套国际有机化合物命名规则
The Geneva conference adopts the first international rules for naming organic compounds