Hydrogen sulfide is a colorless gas. Has a rotten egg smell. Molecular formula: H2-S. Molecular weight 34.08. Relative density 1.19. Melting point -82.9 degrees Celsius. Boiling point -61.8 degrees Celsius. It is soluble in water, soluble in methanol, petroleum solvents and crude oil. The upper limit of combustibility is 45.5%, and the lower limit is 4.3%. The ignition point is 292 degrees Celsius.
Hydrogen sulfide is absorbed quickly through the mucous membrane and slowly absorbed by the skin. Respiratory and eye irritation occurs after inhalation of 70 to 150 mg/m hydrogen sulfide for 1 to 2 hours, and olfactory fatigue and no odor after 2 to 5 minutes. Acute poisoning occurred soon after inhaling 760 mg/m3 and inhaling 1000 mg/m3 for a few seconds, and death occurred due to respiratory paralysis after rapid breathing.
The local irritating effect of hydrogen sulfide on the mucosa is caused by the decomposition of sodium sulfide after contact with the moist mucosa and its own acidity. The systemic effect on the body is to block intracellular respiration, resulting in systemic hypoxia. Because the central nervous system is most sensitive to hypoxia, it is the first to be damaged.