Free-Anionic Duality of Interstitial Electrons Drives Superconductivity in Electride La 3 In - Zhao Liu; Xiang Wang; Yin Yang; Pengcheng Ma; Zhijun Tu; Xinyu Wang; Donghan Jia; Wenju Zhou; Huiyang Gou; Hechang Lei; Qiang Xu; Zhonghao Liu; et al. (Journal of the American Chemical Society, 2026)