New compounds, Bi 3 . 2 4 Ln 2 W 0 . 7 6 O 1 0 . 1 4 , have been found in the systems Bi 2 O 3 -Ln 2 O 3 -WO 3 (Ln=La, Pr, and Nd). They crystallize ostensibly in the orthorhombic (or orthohexagonal) symmetry, e.g. with a=6.9694(1)A, b=4.0242(1)A, c=9.3335(1)A, and Z=1 for Ln=La. At the same time, the lattice forms a superstructure based on a pseudo-fcc subcell with a'~5.6A, where the transformation matrix is (1/2,1/2,-1)/(-1/2,1/2,0)/(1,1,1). However, the cation configuration has proved that the true symmetry is monoclinic (C2/m) with β~90 o . All new compounds undergo two reversible polymorphic transitions at about 980 o C and at 1097-1210 o C depending on Ln. Their electrical conductivity exhibited lower values (about 10 - 4 Scm - 1 at 500 o C) despite the pseudo-fcc subcell in relation to the δ-Bi 2 O 3 type which is the well-known good oxide-ion conductor.