Local structure of nanosized bioglasses doped with yttrium and lanthanum by 29Si and 31P MAS NMR

Spectral Investigations of 60S Bioactive Glass Modified with La and Y Ions

“…Due to the higher degree of oxidation of Y 3+ and La 3+ compared to Ca 2+ , the probability of attachment of two oxygen atoms from a SiO 4 tetrahedron to a Y or La atom increases, which increases the number of Q 2 groups and leads to significant deformations of the tetrahedra and, as a result, broadening of the spectral lines. In the 60S (La2%Y2%) sample, this contribution of Y and La is practically excluded, which may indicate a greater involvement of PO 4 tetrahedra in the formation of chemical bonds with these elements …”

“…In the 60S (La2%Y2%) sample, this contribution of Y and La is practically excluded, which may indicate a greater involvement of PO 4 tetrahedra in the formation of chemical bonds with these elements. 44 Thus, phosphorus, like silicon, is a network-forming element present in the covalent bond −O−Si−O−P−, whereas the elements Ca, Y, and La are network modifiers and are present in the ionic bond −O−Si−O−Ca 2+ (Y 3+ , La 3+ )−O−P−. When 60S bioactive glass is modified with La 3+ and Y 3+ ions, partial fragmentation of PO 4 and SiO 4 tetrahedra in the polymer matrix is observed, along with the formation of isolated nanoclusters.…”