Erayga "arsenous oxide" waxa loola jeedaa iskudhis kiimiko ah oo ka kooban arsenic iyo ogsijiin, oo leh qaacidada molecular As2O3. Waxa kale oo loo yaqaan arsenic trioxide. Arsenous oxide waa walax aad u sun ah oo Kansarka ah oo taariikh ahaan loo isticmaali jiray noocyo kala duwan oo warshado iyo dawooyin ah, in kasta oo isticmaalkeeda si weyn loo xaddiday sannadihii u dambeeyay khataraha caafimaad ee uu leeyahay awgeed.