arsenic disulfide

noun Chemistry.
  1. an orange-red, water-insoluble, poisonous powder, As4S4, As2S2, or AsS, used chiefly in the manufacture of fireworks.
Also called ar·senic mon·o·sul·fide [mon-uh-suhl-fahyd] /ˌmɒn əˈsʌl faɪd/.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018