[är′sōn·ē·əm] (inorganic chemistry) ‒AsH4 A radical which may be considered analogous to the ammonium radical in that a compound such as AsH4OH may form.
arsonium
ar·so·ni·um
(ar-son'ē-ŭm), The positively charged ion, AsH4+; analogous to the ammonium ion, NH4+.