Ba₂[Pd(HS₂O₇)₂(S₃O₁₀)₂]: A Heteroleptic Polysulfatopalladate

Abstract

Key indicators: single-crystal X-ray study; T = 298 K; mean (P-O) = 0.005 A ˚ ; R factor = 0.047; wR factor = 0.127; data-to-parameter ratio = 32.0. Single crystals of-Ba 2 P 2 O 7 , dibarium diphosphate, were obtained under hydrothermal conditions. The structure belongs to the diphosphate A 2 P 2 O 7 series with A being an alkaline earth cation.-Ba 2 P 2 O 7 crystallizes isotypically with-Sr 2 P 2 O 7. All atomic sites have site symmetry m with the exception of two O atoms which reside on general positions. Both Ba 2+ cations are coordinated by nine terminal O atoms from eclipsed diphosphate P 2 O 7 anions to form a three-dimensional network throughout the structure.

Dimers and Chains of Hydrogen bonded [HS2O7]– Anions in the Crystal Structures of M[HS2O7] (M = K, [NH4], [NO], Rb, Cs)

“…The most simple hydrogenpolysulfate is [HS 2 O 7 ] – but also for this anion only a limited number of compounds has been reported. These compounds are [NO 2 ][HS 2 O 7 ] that has been presented already in 1954,4 the tetraselenium compound Se 4 [HS 2 O 7 ] 2 described by Gillespie et al5, and, moreover, the complex metallates Ba 2 [Pd(HS 2 O 7 ) 2 (S 3 O 10 ) 2 ]6 and Li 13 [Zr(HS 2 O 7 )(S 2 O 7 ) 3 ] 3 [Zr(S 2 O 7 ) 4 ]7, the unique non‐metal sulfate As[HS 2 O 7 ][S 2 O 7 ]8, and the ferromagnetically ordering palladium hydrogendisulfate Pd[HS 2 O 7 ] 2 9.…”

“…Within the [SO 4 ] tetrahedron the O–S–O angles excluding the oxygen atom O121 are significantly larger than the ideal tetrahedral angle (109.5°), whereas the angles O–S–O containing the bridging oxygen atom are smaller (Table 1). This observation is in line with the observed tendency that the terminal [SO 4 ] moieties of polysulfate anions deviate from the tetrahedral shape in a sense that the sulfur atom is shifted towards a triangular face of the tetrahedron 6,9. The distortion of the [HSO 4 ] tetrahedron is more distinctive with respect to the larger divergence of the S–O bond lengths.…”

Towards Polysulfuric Acids: The Hydrogentrisulfate Anion [HS3O10]− in A[HS3O10] (A=Na, K, Rb)

“…In their structures the disulfate anion remains unprotonated even in the presence of strongly acidic species like H 2 SO 4 . However, in accordance with the theoretical calculations, the trisulfate anion [S 3 O 10 ] 2− is an even a stronger Brønsted base and, thus, it is not astonishing that in acidic compounds containing both anions [S 2 O 7 ] 2− is the protonated species, for example, in the palladium complex Ba 2 [Pd(HS 2 O 7 ) 2 (S 3 O 10 ) 2 ] . With respect to these findings it is clear that protonated long‐chain polysulfate anions will be hard to obtain.…”

“…In turn, the [S 2 O 7 ] 2− anion is hard to protonate and compounds containing the [HS 2 O 7 ] − anion are rare. They have been obtained more or less accidently, for example, the longer known compounds Se 4 [HS 2 O 7 ] 2 and (NO 2 )[HS 2 O 7 ], as well as the more recent Li 13 [Zr(HS 2 O 7 )(S 2 O 7 ) 3 ] 3 [Zr(S 2 O 7 ) 4 ], As(HS 2 O 7 )(S 2 O 7 ), Ba 2 [Pd(HS 2 O 7 ) 2 (S 3 O 10 ) 2 ], and Pd[HS 2 O 7 ] 2 . A short time ago we could show in a more systematic investigation how such hydrogensulfates can be prepared using SO 3 ‐rich oleum by careful adjustment of the reaction conditions .…”

Oxidizing Rhodium with Sulfuric Acid: The Sulfates Rh2(SO4)3 and Rh2(SO4)3·2H2O

“…Interestingly, only the disulfate ligand leads to the uncommon octahedral palladium coordination. Other reported palladium sulfates like PdSO 4 , Pd(CH 3 SO 3 ) 2 , the complex palladates A 2 [Pd(S 4 O 13 ) 2 ] (A = Na, K, Rb, NH 4 , NO) and Ba 2 [Pd(HS 2 O 7 ) 2 (S 3 O 10 ) 2 ] exhibit the typical square‐planar Pd 2+ surrounding. While all of the oxoanionic palladium compounds mentioned above are divalent, this oxidation state has never been observed for the palladium congener platinum.…”