Cyanide poisoning is poisoning that results from exposure to a number of forms of cyanide. Salts such as sodium cyanide and potassium cyanide are highly toxic. AgCl dissolves in solutions containing ligands such as chloride, cyanide, triphenylphosphine, thiosulfate, thiocyanate and ammonia. There are rare cases of lethal gold poisoning from potassium gold cyanide. Sodium thiosulfate is used in the treatment of cyanide poisoning. Sodium nitrite is an efficient drug in case of cyanide poisoning. The stratosphere is also home to trace amounts of carbon monoxide and hydrogen cyanide. Marston finishes his drink and immediately dies from cyanide poisoning. DDQ reacts with water with release of hydrogen cyanide (HCN), which is highly toxic. Reaction with other pseudohalides such as azide, cyanide, and thiocyanate are possible as well. These substances are capable of decomposing into a sugar molecule and hydrogen cyanide gas. In 1882, Erlenmeyer and Lipp first synthesized phenylalanine from phenylacetaldehyde, hydrogen cyanide, and ammonia. The glycolonitrile then undergoes a spontaneous decomposition to give hydrogen cyanide and formaldehyde. Hydrogen cyanide is produced by adding acid to a solution containing a cyanide salt. Treatment of Hg(I) compounds complexation with strong ligands such as sulfide, cyanide, etc.