Citation: Yamanaka, Shoji; Komatsu, Masaya; Tanaka, Masashi; Sawa, Hiroshi; Inumaru, Kei (2014). High-Pressure Synthesis and Structural Characterization of the Type II Clathrate Compound Na30.5Si136 Encapsulating Two Sodium Atoms in the Same Silicon Polyhedral Cages.. Journal of the American Chemical Society, 136, pp. 7717-7725.