圆底烧瓶Round-bottom flask

球形结构使应力均匀分布，能承受减压和加热时的内外压差，比平底瓶更不易破裂；受热均匀，适合加热套、油浴、水浴加热和磁力搅拌。不能平放，需用软木圈、烧瓶托架或铁夹固定。标准磨口（如 14/23、19/26、24/29，数字为磨口大端直径/磨口长度 mm）使各种仪器可以互相连接组装。

The sphere spreads stress evenly, so it withstands vacuum and heating better than a flat-bottomed flask; it heats uniformly and suits heating mantles, oil and water baths and magnetic stirring. It cannot stand on its own and is held in a cork ring, stand or clamp. Standard-taper joints such as 14/23, 19/26 and 24/29 (wide-end diameter/ground length in mm) let apparatus be assembled interchangeably.

单口烧瓶用于一般反应和蒸馏；两口、三口、四口烧瓶可同时安装冷凝管、温度计、滴液漏斗、搅拌器和气体导管；梨形烧瓶（茄形瓶）底部尖，适合少量液体和旋转蒸发；施兰克瓶带侧管活塞，用于无水无氧操作。

Single-necked flasks serve general reactions and distillation; two-, three- and four-necked flasks take a condenser, thermometer, dropping funnel, stirrer and gas inlet at once; pear-shaped flasks with pointed bottoms suit small volumes and rotary evaporation; and Schlenk flasks with a side-arm stopcock are used for air- and moisture-free work.

使用前检查有无裂纹和星裂，特别是减压操作时；液体量一般为容积的 1/3 到 2/3；加热前加沸石或搅拌子；磨口处可涂少量真空脂以防粘结，但会污染产物，聚四氟乙烯套更清洁。

Check for cracks and star cracks before use, especially under vacuum; fill to between a third and two-thirds; add boiling chips or a stir bar before heating; a little vacuum grease prevents joints seizing but can contaminate products, and PTFE sleeves are cleaner.