Compound formation in the systems of the covalent compounds BeO, AlN, and SiC withR2O3(rare earth oxides) is described. Tentative phase diagrams of the AlNNd2O3 and AlNEu2O3 systems are presented.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/28688/1/0000507.pd