[en] A Sn-25 at.% Li alloy has been fabricated by starting with pure Sn and Li. The alloy was cast into various shapes and sent to researchers in several organizations in the United States and abroad for property measurements. The fabrication procedure involved gradual addition of Li from a separate vessel into a vessel that contained Sn; continuous stirring of the mixture during Li addition increased the Li content of the alloy gradually from 0 to the final value of 25 at.%. The melting temperature of the alloy was 334 C; its density was 6.36 g/cm(sup 3). Results are presented on microstructure, chemical composition, phase distribution, and microhardness of the alloy. Several experiments were conducted to evaluate the chemical reactivity of the alloy with air, water, and steam. Results showed that the alloy undergoes catastrophic oxidation when T and gt;250 C in air and develops an oxide scale in water at temperatures up to 95 C. Exposure in low-pressure steam at 200 C caused significant swelling and cracking of the alloy