Etude de la tétracoordination de l'etain dans deux orthothiostannates: Na 4SnS 4 et Ba 2SnS 4 (α)

The crystal structure of Na ₄SnS ₄ and Ba ₂SnS ₄ (α) were determined. Na ₄SnS ₄ crystallizes in tetragonal system, space group P overline42 ₁c with parameters a = 7.837 Å, c = 6.950 Å, Z = 2 and Ba ₂SnS ₄ (α) in the monoclinic system, space group {P2 ₁}/{c} with a = 8.481 Å, b = 8.526 Å, c = 12.280 Å, β = 112.97° and Z = 4. In these compounds, the crystal structure is built up from discrete orthothiostannate tetrahedra SnS ₄. The structure of Ba ₂SnS ₄ (α) is modified K ₂SO ₄β type.