also: ようそひゃくにじゅうご
noun
iodine-125
A radioactive isotope of iodine used in medical diagnostics and research.
ヨウ素125は放射性医薬品に使われる。
Iodine-125 is used in radiopharmaceuticals.
Older kanji-based spelling with Chinese numerals; rarely used today.
From English 'iodine-125'. The element name ヨウ素 (or older 沃素) is combined with the mass number 125.