A wide range of (Bi2O3)(x)(Nd2O3)((1-x)/2)(MoO3)((1-x)/2) solid solutions with the structure of the anion-conducting bismuth oxide was found in the Bi2O3-Nd2MoO6 join of ternary Bi2O3-MoO3-Nd2O3 system at 0.5 <= x <= 1. In said concentration range the compounds with large (0.92 <= x <= 0.98) and small (0.5 <= x < 0.6) bismuth content are tetragonal at room temperature. In the intermediate concentration range (0.67 <= x <= 0.9) cubic delta-Bi2O3 structure is stabilized at room temperature. It is shown that two tetragonal phases observed at different bismuth concentrations differ from each other in their polymorphism and behavior of the unit cell parameters. All the obtained compounds show high conductivity that reaches 0.1 S/cm (for a cubic sample with x = 0.8 at 800 degrees C). (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.