The reaction of simulated rain with copper, copper patina, and some copper compounds

Rain samples of varying acidities related to the New York City metropolitan area environment for the epochs 1890, 1950, and 1980, as well as two additional variants, were used to study the accelerated reaction with copper, existing patina specimens, and 13 copper compounds (minerals). Cuprite (cuprous oxide) and brochantite (a basic cupric sulfate) formed rapidly under a wide range of conditions. Posnjakite (a hydrated basic cupric sulfate) forms under more limited conditions, sometimes simultaneously with brochantite, but subsequently converts to brochantite. Most copper compounds degrade under low pH (