Osmic tetroxide Meaning, Definition & Usage

Definitions
  1. (Chem.), a white volatile crystalline substance, OsO4, the most stable and characteristic of the compounds of osmium. It has a burning taste, and gives off a vapor, which is a powerful irritant poison, violently attacking the eyes, and emitting a strong chlorinelike odor. Formerly improperly called osmic acid.

Webster 1913