名詞 isomer:

1. a compound that exists in forms having different arrangements of atoms but the same molecular weight

i.so.mer

n.（名詞）
Chemistry Any of two or more substances that are composed of the same elements in the same proportions but differ in properties because of differences in the arrangement of atoms.
【化學(xué)】 同分異構(gòu)體；同分異構(gòu)物：兩種或更多的由相同元素以相同比例組成的，但因原子的排列上的差異而在性質(zhì)上相異的物質(zhì)中的任何一種
Physics Any of two or more nuclei with the same mass number and atomic number that have different radioactive properties and can exist in any of several energy states for a measurable period of time.
【物理學(xué)】 同質(zhì)異能素：兩種或更多種具有相同的質(zhì)子數(shù)和原子數(shù)，但有不同的輻射特性并能在幾種能量狀態(tài)中的任一種里存在一段可測量時(shí)間的原子核中

【引伸】
i.somer.ic