Isolation and Structural Elucidation of the Pnictogen Polysulfate Compounds As ₂ [S ₂ O ₇ ] ₂ [S ₃ O ₁₀ ] and [SeCl ₃ ][Pn(S ₂ O ₇ ) ₂ ] (Pn = Sb, Bi)

Syntheses and structural elucidations for the mixed (poly‐)sulfate As 2 [S 2 O 7 ] 2 [S 3 O 10 ] ( 1 ) and the two disulfate‐containing pnictogenates [SeCl 3 ][Pn(S 2 O 7 ) 2 ] (Pn = Sb ( 3 ) and Bi ( 4 )) are reported. As 2 [S 2 O 7 ] 2 [S 3 O 10 ] ( C 2/ c , a = 2852.0(2) pm, b = 665.05(3) pm, c = 988.49(4) pm, β = 102.531(2)°, V = 1830.2(1) Å 3 ) is the first example of a mixed condensed polysulfate, showing two [As(S 2 O 7 )] units which are bridged by a [S 3 O 10 ] moiety. For direct structural comparison to the binary sulfate, we redetermined the crystal structure of As 2 [SO 4 ] 3 ( 2 ) at 100 K. The pnictogenates [SeCl 3 ][Sb(S 2 O 7 ) 2 ] ( P 2 1 / c , a = 1197.5(2) pm, b = 1435.2(2) pm, c = 927.6(1) pm, β = 99.362(6)°, V = 1572.9(5) Å 3 ) and [SeCl 3 ][Bi(S 2 O 7 ) 2 ] ( P 2 1 / c , a = 1230.86(7) pm, b = 1343.33(7) pm, c = 930.65(6) pm, β = 98.827(2)°, V = 1520.6(1) Å 3 ) are isotypic. They show complex Pn···O coordination, differing from [M(S 2 O 7 ) n ] ( n = 2, 3, 4) species known from other main group elements. Furthermore, they engage in chalcogen bonding with the [SeCl 3 ] + cations. We used quantum chemical calculations (DFT) to get insights on the molecular electrostatic potential surfaces and performed quantum theory of atoms in molecules and natural bond orbital analyses to quantify the strength of the noncovalent interactions.