Isolation of β-Ag3AsSe3, (Me3NH)[Ag3As2Se5], K5Ag2As3Se9, and KAg3As2S5: Novel Solid State Silver Thio- and Selenoarsenates from Solvento-thermal Synthesis

Abstract

Three new solid state silver selenoarsenates and one thioarsenate prepared from hydro- and methanothermal synthesis are described. β-Ag3AsSe3(I) and (Me3NH)[Ag3As2Se5] (II) were synthesized hydrothermally at 110°C from a mixture of AgBF4/3K3AsSe3and AgBF4/3K3AsSe3/6Me3NHCl, while K5[Ag2As3Se9] (III) and K[Ag3As2S5] (IV) were synthesized methanothermally at 110°C from a mixture of AgBF4/3K3AsS3and AgBF4/3K3AsSe3, respectively. β-Ag3AsSe3(I) crystallizes in the orthorhombic space groupPnma(No. 62) witha= 8.111(1) Å,b= 11.344(2) Å,c= 20.728(3) Å,Z= 8,V= 1907(1) Å3. This compound is a new allotrope of α-Ag3AsSe3and has a complex three-dimensional structure composed of distorted trigonal planar and tetrahedral Ag+ions and [AsSe3]3−units. (Me3NH)[Ag3As2Se5] (II) crystallizes in the triclinic space groupP− 1 (No. 2) witha= 10.119(2) Å,b= 18.010(4) Å,c= 14.932(3) Å, α = 110.20 (1)°, β = 103.98(2)°, γ = 99 99(1)°,Z= 2,V= 729.3(8) Å3. The [Ag3As2Se5]n−nanion in (II) has a complex two-dimensional layered structure with tetrahedral Ag+ions and [As2Se5]4−units. K5[Ag2As3Se9] (III) crystallizes in the orthorhombic space groupPnma(No. 62) witha= 12.599(2) Å,b= 12.607(4) Å,c= 14.067(3) Å,Z= 8,V= 2234(1) Å3. The [Ag2As3Se9]5n−nanion in (III) has a two-dimensional layered structure with tetrahedral Ag+ions and two different kinds of selenoarsenate units, [AsSe4]3−and [As2Se5]4−. K[Ag3As2S5] (IV) also crystallizes in the orthorhombic space groupPnma(No. 62) witha= 19.210(2) Å,b= 16.867(2) Å,c= 6.3491(7) Å,Z= 8,V= 2057.2(7) Å3. The [Ag3As2S5]n−nanion in (IV) possesses a complicated two-dimensional structure with tetrahedral Ag+ions and two kinds of thioarsenate ligands, [AsS3]3−and [As3S7]5−. The thermal stability and optical absorption properties of these compounds are reported.