不純 ふじゅん分子 ぶんしではありませんでした
fujumbunshidewārimasendeshita

Noun
Desu Copula

The polite, past negative form of 不純分子

1. Was not an impure element.; Was not an undesirable element.; Was not a troublemaker.

Past/Perfective
Negative
Polite
Formal Register