9634015 Barsoum In the proposed project, the superconducting characteristics of the ternary compounds known as O312sO and OH-phasesO will be studied. The materials have the formula M13M2C2, where M1 is from groups IIIa, IVa, Va, or VIa, and M2 is from groups IIIb, IVb, or Vb. A typical composition is Ti3SiC2. The PIOs group has fabricated dense, single phase samples and studied their atomic structure and properties. These ternary compounds share three properties with high Tc cuprate superconductors. Their atomic structure is layered, their conductivity at room temperature is very high, and their resistivity decreases with decreasing temperature. Because of these similarities, there is a possibility that these materials might also be superconducting. Samples of a variety of 312Os and H-phases will be characterized at temperatures ranging from 4.2 to 300K by four-probe dc resistivity, Hall effect, ac-susceptibility, magnetization and field-induced microwave absorption. %%% The proposed SGER project will study the superconducting characteristics of a group of unusual compounds, which potentially might be a new class of high Tc superconductors. ***