The flux was 50 wt% Bi 2 O 3 -50 wt% B 2 O 3 or K 2 Mo 3 O 10 . K 2 Mo 3 O 10 was made from stoichiometric amounts of K 2 MoO 4 (Alfa Aesar, 99.8%) and MoO 3 (Alfa Aesar, 99.95%) heated in an alumina crucible to 650 • C at 10 • C/min, held for 24 h, and air quenched by pouring the melt into a second alumina crucible (powder X-ray diffraction refinement in the Supporting Information, Figure ). Systems varied from 65-70 wt% flux. The lightly mixed flux and starting powders were placed in a 20 mL platinum crucible with a loose platinum lid. The system was heated in air at 10