nitroprussic

from The Century Dictionary.

• Pertaining to nitric and prussic acids or to nitroferricyanic acid.

from the GNU version of the Collaborative International Dictionary of English.

• adjective (Chem.) Pertaining to, derived from, or designating, a complex acid called nitroprussic acid, obtained indirectly by the action of nitric acid on potassium ferrocyanide (yellow prussiate), as a red crystalline unstable substance. It forms salts called nitroprussides, which give a rich purple color with alkaline sulphides.