ammonium chloride
n.
A slightly hygroscopic, white crystalline compound, NH₄Cl, used in dry cells, as a soldering flux, and as an expectorant. Also called sal ammoniac.

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The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.

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