The two new thiostannate compounds (trenH) 2 Sn 3 S 7 (1) and {[Mn(tren)] 2 Sn 2 S 6 } (2) (tren = tris-2-aminoethylamine) were obtained under solvothermal conditions. Compound 1 crystallizes in the hexagonal space group P6 3 /mmc with a = 13.2642(19), c = 19.078(3) Å, V = 2906.9(7) Å 3 . The layered [Sn 3 S 7 ] 2− anion is constructed by Sn 3 S 4 semi-cubes sharing common edges. The layers are characterized by large hexagonal pores with dimensions of about 11 × 11 Å 2 . Compound 2 crystallizes in the triclinic space group P1 with lattice parameters a = 7.6485(7), b = 8.1062 (7), c = 12.1805(11) Å, α = 97.367(11), β = 103.995(11), γ = 108.762(10) • , V = 676.17(10) Å 3 . The [Sn 2 S 6 ] 4− anion is composed of two edge-sharing SnS 4 tetrahedra and joins two Mn 2+ -centered complexes by Mn-S bond formation. The Mn 2+ cation is in a trigonal-bipyramidal environment of four N atoms of the tren ligand and one S atom of the thiostannate anion. Both compounds are semiconductors with a band gap of 2.96 eV for 1 and of 2.75 eV for 2.

The formation of the thioantimonates [M(tren)Sb4S7] (M = Fe, Zn; tren = tris(2‐aminoethyl)amine) has been studied with in‐situ energy dispersive X‐ray diffraction (EDXRD) under solvothermal conditions. Up to 60 % amine concentration the compound [Fe(tren)Sb4S7] coexists with an unknown crystalline material until the end of the reaction. In the concentration range 70–90 % amine the unknown compound and [Fe(tren)Sb4S7] are formed at the beginning of the reaction and when the unknown compound starts to disappear a new mixed‐valent thioantimonate [Fe(tren)FeSbS4] nucleates and crystallizes. Using a 100 % tren solution only [Fe(tren)FeSbS4] could be identified in the powder patterns. The analysis of the data collected under real conditions clearly shows a strong correlation between the disappearance of the unknown compound and the formation of the mixed‐valent thioantimonate. Evidences are presented that FeII/FeIII redox reactions play an important role for nucleation and crystal growth of a distinct iron‐containing thioantimonate. Because Zn2+ is not redox active the formation processes are different and no crystalline intermediate could be detected.

The new compounds (II) and (IV) are solvothermally synthesized and their crystal structures are determined by single crystal XRD.