[RbSr3X][(BS3)2] (X = Cl, Br): two salt-inclusion thioborates with large birefringence and structure transformation from centrosymmetric to asymmetric

[RbSr 3 X][(BS 3 ) 2 ] (X = Cl, Br), two salt-inclusion chalcogenides with CS-to-NCS structure transformation were obtained.