Network structure with mixed bond-angle linkages in MoO3–ZnO–B2O3 glasses: Neutron diffraction and reverse Monte Carlo modelling

• The basic network former units are trigonal BO3 and tetrahedral BO4, MoO4, ZnO4.
• BO3 and BO4 form superstructure units, a small part is in isolated BO3 triangles.
• BO4/BO3 increases with increasing B2O3 content.
• ZnO takes part in the glassy structure as network former.
• Mixed[4]Mo–O–[3, 4]B,[4]Mo–O–[4]Zn,[3, 4]B–O–[4]Zn bond-linkages are formed.

The short- and medium-range order of glassy MoO3–ZnO–B2O3 has been studied by neutron diffraction and reverse Monte Carlo simulation. The partial atomic pair correlation functions and coordination numbers are presented, not yet reported for this system. We have established that the first neighbour distances do not depend on concentration within limit of error, the actual values are rB–O = 1.38 Å, rMo–O = 1.72 Å and rZn–O = 1.97 Å. It is found that ZnO takes part in the glassy structure as network former, ZnO4 tetrahedral are linked both to MoO4 and to BO3&BO4 groups. It is revealed that BO4/BO3 increases with increasing B2O3 content. We have found that only small amount of boroxol ring is present, BO3 and BO4 groups are organized into superstructure units, and a small part is in isolated BO3 triangles The BO3 and BO4 units are linked to MoO4 or ZnO4, forming mixed[4]Mo–O–[3, 4]B,[4]Mo–O–[4]Zn,[3, 4]B–O–[4]Zn bond-linkages.