were drawn using VESTA, as shown in Fig. . Here, a novel 3-ring structure with three B 4 units in YBO 3 is indicated by black dashed lines. The solid-state 11 B magic-angle spinning (MAS) NMR spectrum of a-La30 glass was mea-7 sured to estimate the boron species (Fig. ). The 11 B MAS NMR spectra of the other 8 glasses (a-La50, a-La60, and a-Y50) were reported in our previous study. The spectral .