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blue vitriol

noun Chemistry, Mineralogy.
  1. a salt, copper sulfate, CuSO4⋅5H2O, occurring naturally as large transparent, deep-blue triclinic crystals, appearing in its anhydrous state as a white powder: used chiefly as a mordant, insecticide, fungicide, and in engraving.

Origin of blue vitriol

First recorded in 1760–70
Also called blue copperas, chalcanthite, cupric sulfate.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
British Dictionary definitions for blue copperas

blue vitriol

noun
  1. the fully hydrated blue crystalline form of copper sulphate
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
blue copperas in Science

blue vitriol

  1. A blue, crystalline compound of copper sulfate. Blue vitriol is soluble in water, and is a very important industrial salt of copper. It is used in insecticides and germicides, in electrolytes for batteries, and in electroplating baths. Chemical formula: CuSO4·5H2O.
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