Synthesis and Characterization of the Orthorhombic Sn<sub>3</sub>O<sub>4</sub> Polymorph
Yang‐Shin Liu, Akira Yamaguchi, Yue Yang, An Niza El Aisnada, Sho Uchida, Hideki Abe, Shigenori Ueda, Kenji Yamaguchi, Toyokazu Tanabe, Masahiro Miyauchi
Abstract
Abstract An unexplored tin oxide crystal phase (Sn 3 O 4 ) was experimentally synthesized via a facile hydrothermal method. After tuning the often‐neglected parameters for the hydrothermal synthesis, namely the degree of filling of the precursor solution and the gas composition in the reactor head space, an unreported X‐ray diffraction pattern was discovered. Through various characterization studies, such as Rietveld analysis, energy dispersive X‐ray spectroscopy, and first‐principles calculations, this novel material was characterized as orthorhombic mixed‐valence tin oxide with the composition Sn II 2 Sn IV O 4 . This orthorhombic tin oxide is a new polymorph of Sn 3 O 4 , which differs from the reported conventional monoclinic structure. Computational and experimental analyses showed that orthorhombic Sn 3 O 4 has a smaller band gap (2.0 eV), enabling greater absorption of visible light. This study is expected to improve the accuracy of hydrothermal synthesis and aid the discovery of new oxide materials.