mǎ lín
morpholine (chemistry) (loanword)
吗
mǎ
used in 嗎啡|吗啡[ma3 fei1]
啉
lín
used in the transliteration of the names of organic compounds such as porphyrin 卟啉[bu3 lin2] and quinoline 喹啉[kui2 lin2]