“…These include at least five stable crystalline phases: Bi 24 B 12 O 39 (boron sillenite) [8,9], Bi 4 B 2 O 9 [8,10], Bi 3 B 5 O 12 [8,11], BiB 3 O 6 (bismuth triborate) [5,8,[12][13][14], Bi 2 B 8 O 15 (bismuth octaborate) [8,[15][16][17] and one metastable phase (that was missing in original phase diagram given in reference [8]): BiBO 3 (bismuth orthoborate), and its two polymorphs (BiBO 3 -I and BiBO 3 -II) [18][19][20]. A number of earlier studies have reported the density, thermal, optical and structural studies of Bi 2 O 3 -B 2 O 3 glasses [1,[21][22][23][24][25][26] and melts [27].…”