The aeration of dilute solutions of disodium ethylenebisdithiocarbamate yields hexahydro-1,3,6-thiadiazepine-2,7-dithione (I), polymeric I, 2-imidazolidinethione, and elemental sulphur. I with ammonia gives mainly hexahydro-1,3,5-triazepine-2,4-dithione. I and polymeric I have high antifungal activity.