<Dd> H S ⇌ HS + H </Dd> <P> Hydrogen sulfide gas and the hydrosulfide anion are extremely toxic to mammals, due to their inhibition of the oxygen - carrying capacity of hemoglobin and certain cytochromes in a manner analogous to cyanide and azide (see below, under precautions). </P> <P> Reduction of elemental sulfur gives polysulfides, which consist of chains of sulfur atoms terminated with S centers: </P> <Dl> <Dd> 2 Na + S → Na S </Dd> </Dl>

A sulfur atom has how many valence electrons