Local environment of strontium ions in borosilicate and aluminophosphate glasses

Parameters of the local environment of the Sr 2+ ions in borosilicate glasses with a high level waste surrogate were determined by analyzing the of X-ray absorption fine structure spectra. It is found that the Sr 2+ ions mostly have an oxygen environment with a trigonal bipyramidal configuration; the average Sr-O distance in the first coordination shell is about 2.53–2.54 Å. The second coordination shell of strontium in the glasses is weak; the nearest neighboring atom is located at a distance of 3.55–3.58 Å. In the structure of all the studied glasses, the first coordination shell of strontium is split into two subshells because of a distortion of the coordination polyhedron, while the second and subsequent coordination shells become apparent upon an increase in the SrO concentration.