Fine-tuning of optical properties with salts of discrete or polymeric, heterobimetallic telluride anions [M-4(mu(4)-Te)(SnTe4)(4)](10-) (M = Mn, Zn, Cd, Hg) and (3)(infinity){[Hg-4(mu(4)-Te)(SnTe4)(3)](6-)

Compounds with first discrete M/Sn/Te anions-exhibiting a series of optical absorption energies in the semiconductor range-are obtained by reactions of K+ or Rb+ salts of [SnTe4](4)(-) with MCl2 ( M = Mn, Zn, Cd, Hg) in H2O or H2O-MeOH; larger Cs+ cations provoke the formation of a polymeric derivative of the ternary anionic structure.