Temperature symmetry breaking and properties of lead-free organic–inorganic hybrids: bismuth( iii ) iodide and antimony( iii ) iodide: (S(CH 3 ) 3 ) 3 [Bi 2 I 9 ] and (S(CH 3 ) 3 ) 3 [Sb 2 I 9 ]

Two novel lead-free ferroelastic materials, (S(CH 3 ) 3 ) 3 [Sb 2 I 9 ] and (S(CH 3 ) 3 ) 3 [Bi 2 I 9 ], which exhibit reach sequences of phase transitions and reveal semiconducting properties, have been synthesized.