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Chemistry

Phase Diagrams of Binary Mixtures: Interpreting Eutectic and Peritectic Points

Quick fact

At a eutectic point, a liquid mixture of two components solidifies into two separate solid phases at a single, fixed temperature—the lowest melting point achievable for that mixture. This is why solder alloys melt at temperatures far below that of pure lead or pure tin.

Why this is interesting

You’ve probably seen a chocolate bar melt and re‑solidify, but did you know that mixing two metals—or even two other substances—can make them melt at a lower temperature than either one alone? What’s going on?