With spray bottles, they applied both cupric nitrate and ferric nitrate to the metal, then distributed and smoothed the sizzling liquid with mop-shaped brushes.
New York Times(Jul 01, 2015)
It’s so faded and rusty that it looks like a strong breeze would make it disappear in a cloud of ferric dust.
Washington Post(Apr 19, 2015)
Footage from locals captures the cloud, which included nitric acid and ferric chloride, causing the cloud's bright colour.
BBC(Feb 13, 2015)