arsenic acid
Chemical term for the compound H₃AsO₄. Used in specialized chemistry contexts.
Arsenic acid is highly toxic, so it must be handled with care.
Standard modern spelling using the katakana ヒ for the element name.
Older kanji spelling using 砒 (arsenic); now largely replaced by ヒ酸 in chemical contexts.
Compound of ヒ (arsenic, from German 'Arsen') + 酸 (acid).