Abstract <p>This paper presents, the Gibss–Thomson Coefficient, solid-liquid interfacial energy and grain boundary energy of solid tin phase in tin–magnesium–bismuth ternary alloy systems, which were calculated by using the equilibrated grain boundary groove shapes obtained in a radial heat-flow system. Chemical analysis of solid Sn was proved with energy dispersive X-Ray analyzer. The thermal conductivity of the eutectic solid and the thermal conductivity ratio of eutectic liquid to the eutectic solid in Sn–1.56Mg–1.00Bi (at %) eutectic alloy at its eutectic melting temperature were measured with a radial heat flow apparatus and a Bridgman-type growth apparatus. The Gibbs–Thomson coefficient, solid–liquid interfacial energy and grain boundary energy of solid Sn in equilibrium with Sn–Mg–Bi eutectic liquid were determined to be (8.4 ± 0.6) × 10^–8 K m, (104.5 ± 12.5) × 10^–3 and (190.3 ± 24.7) × 10^–3 J m^–2 respectively from observed grain boundary groove shapes. The calculated results were in good compatibility with the previous works.</p>