Dihydroxydisulfane

Dihydroxydisulfane or hypodithionous acid is a reduced sulfur <a href="/facts/Oxyacid/p0bMdwSx">oxyacid</a> with sulfur in a formal <a href="/facts/Oxidation_state/W53W6s6V">oxidation state</a> of +1, but the <a href="/facts/Valence_(chemistry)/ck7cHByj">valence</a> of sulfur is 2. The structural formula is HO−S−S−OH, with all atoms arranged in a chain. It is an isomer of <a href="/facts/Thiosulfurous_acid/dEyMFxlB">thiosulfurous acid</a> but is lower in energy. Other isomers include HOS(=O)SH, HOS(=S)OH, and HS(=O)2SH. <a href="/facts/Disulfur_monoxide/ez5v6KrH">Disulfur monoxide</a>, S2O, can be considered as the anhydride. Unlike many of these other reduced sulfur acids, dihydroxydisulfane can be formed in a pure state by reacting <a href="/facts/Hydrogen_sulfide/UbCqjMMk">hydrogen sulfide</a> with <a href="/facts/Sulfur_dioxide/jDK1fIDs">sulfur dioxide</a> at −70 °C in <a href="/facts/Dichlorodifluoromethane/KdMmfral">dichlorodifluoromethane</a>.

H2S + SO2 → H2S2O2
Dihyroxydisulfane may exist in an equilibrium with thiosulfurous acid.
Organic derivatives such as dimethoxydisulfane, diaceto disulfide, and bis(trifluoroaceto) disulfide also exist.
The conjugate bases are called disulfanediolate HS2O−2 and hypodithionite S2O2−2.

Dihydroxydisulfane open-in-new

Dihydroxydisulfane