酰 (xiān): acyl (chemistry)

Meanings

1 acyl (chemistry)
2 acid radical
3 -acyl (suffix)

Characters

酰

xiān

acyl / acid radical

Examples

HSK 7-9

乙酰是醋酸去掉羟基后的基团。

Yǐ xiān shì cù suān qùdiào qiǎngjī hòu de jī tuán.

Acetyl is the group left when acetic acid loses its hydroxyl.

HSK 7-9

氨基酸的酰胺键是蛋白质的基础。

Ānjīsuān de xiān àn jiàn shì dànbáizhì de jīchǔ.

The amide bond between amino acids is the basis of proteins.

Tips

usage

Pure chemistry term, you'll only meet it in compounds like 乙酰 (acetyl), 酰胺 (amide), or 酰基 (acyl group). Older texts use 醯 instead.

mistakes

Pronounced xiān, not xī. The 1st-tone reading trips up native speakers too because the 山 component looks like it could be a phonetic, it isn't.

Components

radical

酉 yǒu

wine vessel; tenth earthly branch

Left wine-jar radical, the indexing element: a pictograph of a narrow-necked fermentation vessel. The chemical-naming convention adopted 酉 for the family of organic compounds related to alcohol, acids and fermentation. Same family as 酒 wine, 酸 acid, 醋 vinegar, 酶 enzyme, the entire biochemistry cluster derives from this jar.

phonetic

先 xiān

first

Right 先 supplies the sound directly: xiān to xiān. Pure phonetic, coined by 20th-century chemists naming acyl groups (R-CO-, the fragment linking an acid to other molecules). Same phonetic in 选, 洗.