It is a member of the polythionates, which have the general formula [Sn(SO3)2]2-.

Other members include trithionite (n = 1), pentathionate (n = 3), hexathionate (n = 4).

[1] Sodium tetrathionate is formed by the oxidation of sodium thiosulfate (Na2S2O3), e.g. by the action of iodine:[1] The reaction is signaled by the decoloration of iodine.

This reaction is the basis of iodometric titrations.

Other methods include the coupling of sodium bisulfite with disulfur dichloride:[1] The ion has ideal C2 symmetry, like H2S2.