mercuric chloride

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A poisonous white crystalline compound, HgCl₂, used as an antiseptic and a disinfectant, in insecticides, preservatives, and batteries, and in metallurgy and photography.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun inorganic chemistry The salt of mercury and hydrochloric acid, HgCl2

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a white poisonous soluble crystalline sublimate of mercury; used as a pesticide or antiseptic or wood preservative