The investigation was concerned with the compounding, crystal growth, characterization, and evaluation of compounds formed between the rare-earth elements and elements of chemical Groups V and VI. Special emphasis is placed on providing basic information to make possible the ultimate development of useful solid-state electronic devices based on these materials. In sampling the members of the rare-earth family, the elements cerium, neodymium, samarium, gadolinium, erbium, and ytterbium were used in the preparation of representative compounds and alloys with anions, such as, selenium, tellurium, oxygen, arsenic, antimony, phosphorus, and nitrogen. Single crystal, bulk, and thin-film specimens were prepared, and details regarding methods of compounding and crystal growth are given. Several applications of rareearth compounds and alloys studied are suggested.