Synthesis and Crystal Structure of Ca(en) 4 Ca(en) 3 [Sn 2 Se 6 ] and Ca(en) 4 Se 4 in Superheated and Supercritical Ethylenediamine

Two new compounds Ca(en) 4 Ca(en) 3 [Sn 2 Se 6 ] ( 1 ) and Ca(en) 4 Se 4 ( 2 ) were synthesized under superheated and supercritical solvothermal conditions in ethylenediamine. Compound 1 crystallizes in triclinic space group P $\bar{1}$ (No. 2) with a = 10.2708(4) Å, b = 12.2739(5) Å, c = 16.3103(6) Å, α = 93.576(3)°, β = 90.609(3)°, γ = 109.269(4)°, Z = 1 and V = 1936.09(13) Å 3 . The crystal structure of 1 comprises of isolated [Sn 2 Se 6 ] 4– anion as well as Ca(en) 4 2+ and Ca(en) 3 2+ cations. Compound 2 crystallizes in the orthorhombic space group Fdd 2 (No. 43) with a = 27.5034(10) Å, b = 9.2738(6) Å, c = 16.9880(6) Å, Z = 8 and V = 4333.0(4) Å 3 . The crystal structure of 2 consists of Se 4 2– anion and Ca(en) 4 2+ cations. In both 1 and 2 the selenostannate, [Sn 2 Se 6 ] 4– and the tetraselenide, Se 4 2– anions are interconnected to the amine group of Ca(en) 4 2+ and/or Ca(en) 3 2+ via hydrogen bridges forming a three‐dimensional network. Whereas in 1 CaO serves as source for Ca 2+ , was 2 synthesized using the Zintl phase CaSi 2 and selenium powder.