Optical nonlinearity in Cu₂CdSnS₄ and α/β-Cu₂ZnSiS₄: diamond-like semiconductors with high laser-damage thresholds.

Cu2CdSnS4 and α/β-Cu2ZnSiS4 meet several criteria for promising nonlinear optical materials for use in the infrared (IR) region. Both are air-stable, crystallize in noncentrosymmetric space groups, and possess high thermal stabilities. Cu2CdSnS4 and α/β-Cu2ZnSiS4 display wide ranges of optical transparency, 1.

Bis[2,2'-(2-amino-ethyl-imino)-di(ethyl-ammonium)] di-μ-sulfido-bis[disulfido-stannate(IV)].

The asymmetric unit of the title compound, (C(6)H(20)N(4))(2)[Sn(2)S(6)], comprises half of a [Sn(2)S(6)](4-) anion and a diprotonated tris-(2-amino-eth-yl)amine cation. The anion lies on an inversion center, while the atoms of the cation occupy general positions. An intra-molecular N-H⋯N hydrogen bond is observed in the cation.

Cu(2)ZnSiS(4).

Single crystals of Cu(2)ZnSiS(4), dicopper(I) zinc silicon tetrasulfide, have been prepared via high-temperature solid-state synthesis. Cu(2)ZnSiS(4) was found to have the wurtz-stannite structure type, like that of Li(2)CdGeS(4), Li(2)CdSnS(4), and Cu(2)CdSiS(4). Each sulfur anion is tetra-hedrally coordinated by two Cu cations, one Si cation, and one Zn cation, forming a three-dimensional honeycomb structure.