Sb-Triggered β-to-α Transition: Solvothermal Synthesis of Metastable α-Cu2Se.

Monoclinic α-Cu2Se and cubic β-Cu2Se are solvothermally synthesized by reaction of CuCl2 and Se powder in en in the presence, and absence of SbCl3, respectively (autoclave, 200 °C, 14 h).