Abstract
The complete set of Faber-Ziman partial pair distribution functions for a rare earth oxide liquid
were measured for the first time by combining aerodynamic levitation, neutron diffraction, high
energy x-ray diffraction and isomorphic substitution using Y2 O3 and Ho2 O3 melts. The average Y-
O coordination is measured to be 5.5(2), which is significantly less than the octahedral coordination
of crystalline Y2 O3 (or Ho2 O3 ). Investigation of high temperature La2 O3 , ZrO2 , SiO2 , and Al2 O3
melts by x-ray diffraction and molecular dynamics simulations also show lower-than-crystal cation-
oxygen coordination. These measurements suggest a general trend towards lower M-O coordination
compared to their crystalline counterparts. It is found that this coordination number drop is larger
for lower field strength, larger radius cations and is negligible for high field strength (network
forming) cations. These findings have broad implications for predicting the local structure and
related physical properties of metal-oxide melts and oxide glasses.
