evernic

The silver-salt, AgO, C₁₈H₉O₇, is obtained as a white precipitate, on addition of nitrate of protoxide of silver to everninate of ammonia. If evernic acid be boiled with strong alcohol, containng a few pieces of caustic potassa, until the whole is perfectly dissolved, and carbonic acid be passed into the liquid until the potassa is neutralized, and the liquid be then concentrated, long, brown, prismatic crystals are deposited, after some time (the mother-liquor containing orcin); these may be obtained pure by washing with water, and recrystallization from alcohol.

1850, Justus Freiherr von Liebig, Annual Report of the Progress of Chemistry, page 71