ANb 2 (PS 4 )(S 2 ) 3 (A = K, Rb, Cs): the first Nb-based NLO thiophosphates with [NbS 2 (S 2 ) 3 ] and [Nb 2 PS 6 (S 2 ) 4 ] units exhibiting tri-state structural transformation and high performance

The first NLO Nb-based thiophosphates ANb 2 (PS 4 )(S 2 ) 3 (A = K, Rb, Cs) exhibit tri-state structural transformation and large SHG responses, showing high potentials for IR NLO application.