[en] The magnetic, electrical, and thermodynamic properties of several metallic rare earth compounds with anomalous lattice constants such as YbC₂, YbAl₃, YbAl₂, YbB₄, YbCu₂Si₂, CeB₄, CeN, CeCu₂Si₂, and EuCu₂Si₂ are examined. Though diverse in composition and crystal structure, these compounds exhibit qualitatively similar anomalies in their electronic properties. Apart from an ''abnormal'' lattice constant, they show a large paramagnetic susceptibility (sometimes with Curie-Weiss behavior at high temperatures), yet there is no evidence of magnetic order. The low temperature magnetization curves (M vs. H) are linear and do not saturate in the region where μ H much more than k/sub B/T, as is expected for non-interacting rare earth ions. The resistivity curves exhibit large departures from a simple T law, indicating a large magnetic scattering contribution. The electronic specific heat coefficient and the thermopower are large, suggesting a large density of states at the Fermi level. The experimental data are found to be in good agreement with what is expected qualitatively from fluctuations of the rare earth ion shell between two integral valence states. (U.S.)