Patent Number: 
Section: claims

1. A mixed-layered bismuth oxy-iodine material, comprising a chemical assemblage at an atomistic scale of at least two different Bi—O—I lattice phases. 2. The material of claim 1, wherein the at least two different Bi—O—I lattice phases comprise BiOI and Bi507I lattice phases. 3. The material of claim 2, wherein the relative proportions of the BiOI and Bi5O7I lattice phases is 85-80 mole % BiOI and 15-20 mole % Bi507I. 4. The material of claim 1, wherein the mixed-layered bismuth oxy-iodine material has an elemental composition comprising 17-22 wt % iodine, with the balance comprising primarily bismuth and oxygen. 5. The material of claim 1, wherein the mixed-layered bismuth oxy-iodine material 20 has a bismuth-to-iodine (Bi:I) molar ratio of between 1.64 and 2.13. 6. The material of claim 1, wherein the mixed-layered bismuth oxy-iodine material has a iodine solubility equal to or less than 15 ppb, after exposing the material for 3 days to deionized water at a temperature of 25° C. or lower. 7. The material of claim 1, wherein the mixed-layered bismuth oxy-iodine material has a iodine solubility equal to or less than 100 ppb, after exposing the material for 3 days to deionized water at a temperature of 94° C. or lower. 8. The material of claim 1, wherein the mixed-layered bismuth oxy-iodine material has a iodine solubility equal to or less than 100 ppm, after exposing the material for 3 days to deionized water plus 0.005 molar sodium sulfate at a temperature of 25° C. or lower. 9. The material of claim 1, wherein the mixed-layered bismuth oxy-iodine material has a iodine solubility equal to or less than 1000 ppm, after exposing the material for 3 days to deionized water plus 0.005 molar bicarbonate at a temperature of 25° C. or lower. 10. The material of claim 1, wherein the mixed-layered bismuth oxy-iodine material has a iodine solubility equal to or less than about 1 ppm, after exposing the material for 3 days to deionized water plus 0.005 molar chloride at a temperature of 25° C. or lower. 11. The material of claim 1, wherein the iodine in the mixed-layered bismuth oxy-iodine material comprises radioactive 129I.