Crystal Structure and Chemical Stabilization of the Triple Salt (KHSO 5 ) 2 ⋅KHSO 4 ⋅K 2 SO 4

The title compound, a versatile and chemically stabilized oxidant, which is used technologically on a large scale, builds up an intercalation‐type of crystal structure with alternating sheets of sulfate and peroxomonosulfate anions, interspersed by the potassium cations. The sulfate ions are joined by a very short but nonetheless probably asymmetric hydrogen bond. At room temperature, the HSO $\rm{_{5}^{-}}$ ions show dynamic orientational/conformational disorder in the area of the hydrogenperoxo group, which disappears at 100 K. The chemical stabilization of the triple salt is ascribed to shielding of the HSO $\rm{_{5}^{-}}$ ions effected by the intercalation between the sulfate sheets and, furthermore, by the large and abundant K + ions of this potassium‐rich compound.