The solubility of sulfates decreases down the group.• Magnesium sulfate is soluble• Calcium sulfate is slightly soluble• Strontium sulfate and barium sulfate are insoluble
Barium Meals
Barium ions are toxic to humans but barium sulfate is insoluble. Patients are given a barium meal before an X-ray. Barium sulfate absorbs X-rays strongly, so the outline of the gut (a soft tissue) shows up clearly.Solubility Table