How to Write 酰 (xiān) — Meaning “acyl”

Imagine a bottle of wine (酉) with a label that says 'First (先) come the acids – acyl!' The 'first' (先) part reminds you that an acyl group is the reactive part of an acid. You can also think of 'see-ahn' (sounds like xiān) and picture a scientist saying 'See, an acyl group!'

The left radical 酉 has 7 strokes; write its horizontal top stroke first, then the left vertical, then inner strokes (the two horizontal lines and bottom horizontal). The right part 先 has 6 strokes; start with the top left stroke, then the horizontal, then the vertical stroke through the center, then the two strokes for '儿' at the bottom. A common mistake is making the 酉 too wide; keep it narrow so the whole character stays balanced.

酰 (xiān) means 'acyl' and is used in chemistry, while 酕 (máo) is rarely used and means 'drunk' or refers to a type of wine. 酖 (dān/chén) means 'to drink' or 'poisoned wine', and also appears in ancient texts. Visually, 酰 has 先 on the right, 酕 has 毛 (hair) on the right, and 酖 has 冘 (a person carrying a load) on the right; their right-side components are completely different.

酰 appears almost exclusively in chemical terminology, such as 酰胺 (amide), 乙酰 (acetyl), and 酰基 (acyl group). You will encounter it in textbooks, scientific papers, and product names in chemistry or medicine. It is not used in daily conversation, so it is a specialized character for students and professionals in chemistry-related fields.

Common words containing 酰 include: 酰胺 (xiān àn) — amide; 乙酰 (yǐ xiān) — acetyl; 酰基 (xiān jī) — acyl group.