Strontium Thionates

Description

The "thionite" and "thionate" salts of strontium include:
Strontium dithionite=SrS2O4
Strontium dithionate= =SrS2O6
Strontium tetrathionate=SrS4O6
Strontium dithionite, SrS2O4, may be prepared by the reaction of strontium chloride with sodium dithonite:
SrCl2+ Na2S2O4 ? SrS2O4+ 2NaCl
Alternatively, it may be prepared by the solid-state reaction of SO2 gas upon the sulfite:
Sr(HSO3)2(solid)+ SO2(gas)+ heat
? SrS2O4(solid)+H2O
This reaction could probably be carried out in solution as well. However, the reaction would be dependent upon the pH of the solution and a pH of about 4.5 would produce the compound:
SrCl2+ 2(NH4)2SO3+ SO2 ? SrS2O4+ 2NH4Cl+H2O
The description of the physical and chemical properties of this salt are completely lacking in the scientific and technological literature. Strontium dithionite is mentioned in a few patents as a reducing agent to decolorize certain plastics. The older reference books like Sidgewick or Remy (1933 or 1950) do not list such a compound as being known. It has no CAS number and has no commercial value.