“…For example, a series of superconductors A x (NH 3 ) y Fe 2 Se 2 (A = Li, Na, Ca, Sr, Ba, Yb, and Eu) have been successfully obtained by using liquid ammonia method, [1][2][3] which otherwise cannot be synthesized by the high-temperature route. [4][5][6][7][8][9][10][11][12] For Na x (NH 3 ) y Fe 2 Se 2 , enhanced superconducting transition temperature (T c ) of 46 K was observed. [1] The metal intercalation by other lowtemperature methods using pyridine, ethanediamine, and hexamethylenediamine as solvents was then demonstrated to be equivalently effective in inducing superconductivity with similar T c in Li x (C 5 H 5 N) y Fe 2−z Se 2 , [13] A x (C 2 H 8 N 2 ) y Fe 2−z Se 2 (A = Li, Na), [14,15] and Li x (C 6 H 16 N 2 ) y Fe 2−z Se 2 .…”