M[B2(SO4)4] (M = Mn, Zn)—Syntheses and Crystal Structures of Two New Phyllosilicate Analogue Borosulfates

Abstract

Borosulfates are a rapidly expanding class of silicate analogue materials, where the structural diversity is expected to be at least as large as known for silicates. However, borosulfates with cross-linking of the anionic network into two or even three dimensions are still very rare. Herein, we present two new representatives with phyllosilicate analogue topology. Through solvothermal reactions of ZnO and MnCl2∙4H2O with boric acid in oleum (65% SO3), we obtained single-crystals of Mn[B2(SO4)4] (monoclinic, P21/n, Z = 2, a = 8.0435(4), b = 7.9174(4), c = 9.3082(4) Å, β = 110.94(1)°, V = 553.63(5) Å3) and Zn[B2(SO4)4] (monoclinic, P21/n, Z = 2, a = 7.8338(4), b = 8.0967(4), c = 9.0399(4) Å, β = 111.26(1)°, V = 534.36(5) Å3). The crystal structures reveal layer-like anionic networks with alternating vierer- and zwölfer-rings formed exclusively by corner-linked (SO4)- and (BO4)-tetrahedra.

Ni[B2(SO4)4] and Co[B2(SO4)4]: Unveiling Systematic Trends in Phyllosilicate Analogue Borosulfates

“…These are Zn[B 2 (SO 4 ) 4 ], [11] and Mn[B 2 (SO 4 ) 4 ]. [11] Ni II was replaced by Zn II , and Mn II ,r espectively,a nd the two in silico structures were optimized. In addition, asM g[B 2 (SO 4 ) 4 ]i si sotypic to Ni[B 2 (SO 4 ) 4 ] with the chargec ompensation cations located between the layers, the Co II atoms in Co[B 2 (SO 4 ) 4 ]w erea lso replaced by Mg II yielding another in silico modification.…”

“…[8,9] For purely S-O-B bridgeds pecies the number decreases to 39. [8,10,11] To stick to the latter,t he majority of these borosulfates exhibit oligomeric oxoanionso ri nfinite anionic chains. Further,b ranching of the anionic network is rare.…”

“…[8a] Phyllosilicate analogue substructures of purely S-O-B bridged speciesa re only knownf or the compounds Ca[B 2 (SO 4 ) 4 ], [8b] Mg[B 2 (SO 4 ) 4 ], [9d] Zn[B 2 (SO 4 ) 4 ], [11] and Mn[B 2 (SO 4 ) 4 ]. [11] In this work, we report two new transition-metal representatives with phyllosilicatea nalogue anionic substructures. Ni[B 2 (SO 4 ) 4 ]a nd Co[B 2 (SO 4 ) 4 ]f eature anionic layers of four-and twelve-membered rings formed by vertex-shared (SO 4 )-and (BO 4 )-tetrahedra.B oth anionic substructures are homeotypic to each other.H owever,t he positions of the divalent cationsw ith respectt ot he anionic layers differ significantly.A ll cobalt cations reside within the centero ft he twelve-membered rings, whereas the nickel cations are exclusively located above and underneath the rings.…”

“…To the best of our knowledge, to date only 57 borosulfates have been properly characterized by means of X‐ray single‐crystal analysis [8, 9] . For purely S‐O‐B bridged species the number decreases to 39 [8, 10, 11] . To stick to the latter, the majority of these borosulfates exhibit oligomeric oxoanions or infinite anionic chains.…”

“…Li[B(SO 4 ) 2 ] is, thus far, the only borosulfate exhibiting a 3D network of perfectly alternating (SO 4 )‐ and (BO 4 )‐tetrahedra [8a] . Phyllosilicate analogue substructures of purely S‐O‐B bridged species are only known for the compounds Ca[B 2 (SO 4 ) 4 ], [8b] Mg[B 2 (SO 4 ) 4 ], [9d] Zn[B 2 (SO 4 ) 4 ], [11] and Mn[B 2 (SO 4 ) 4 ] [11] …”