Halogen regulation triggers structural transformation from centrosymmetric to noncentrosymmetric switches in tin phosphate halides Sn2PO4X (X = F, Cl)

A tin phosphate halide, centrosymmetric Sn 2 PO 4 F, was successfully transformed into noncentrosymmetric Sn 2 PO 4 Cl with excellent comprehensive performance by the substitution of F − with Cl − .