Selenides of La, Er, and Y, and tellurides of La, Er, Gd, and Y were prepared by direct reaction of the elements. Measured electrical characteristics indicate semiconducting behavior, with the possibility that a wide range of properties can be obtained within these series of rare earth compounds. Observed room‐temperature resistivities, for example, ranged from about 10−4 ohm‐cm for and to the insulator range for . All the compounds prepared possess high melting points (1400°–2000°C) and exhibit good thermal stability. The dissociation pressure of at its melting point appears to be as low as 0.01 atm.