[en] Some pseudobinary and pseudoternary oxidenitrides (CeN-CeO₂; LaN-Ln₂O₃; CeN-Ln₂O₃, Ln = La, Y; and YN-Ln₂O₃, Ln = La, Lu, Y, Sc) were prepared in Ta, Nb, or Mo containers at temperatures between 1,500 and 1,800 degrees C and characterized by X-ray powder diffraction. Electrical and magnetic properties of two oxidenitrides, LaO_0.31N_0.69 (I) and LaO_0.45N_0.55 (II), were determined over the temperature range 2-300 K. Both are weakly paramagnetic and metallic. Room temperature (300 K) resistivities for I and II are 4.8 x 10^-3 and 5.9 x 10^-5 Ω cm, respectively. As the temperature is lowered, resistivities of LaO_xN_1-x initially decrease linearly. 23 refs., 5 figs., 2 tabs