Coronic acid

Coronic acid was a type of acid that was harmful to Sontarans, causing damage to their bodies and their armour, typically killing them on contact (although Group Marshal Stike was able to survive this and many other injuries). The substance produced large showers of white sparks, similar to burning magnesium.

It was used against them in 1985 by Chessene of the Franzine Grig (TV: The Two Doctors), and in 2371 by Raghi defence forces. (PROSE: Lords of the Storm)