Exploring Main Group Metal Borosulfates: Similarities and Differences of Two New Borosulfates M[B₂O(SO₄)₃] (M = Sr, Pb)

Abstract

The first strontium borosulfate Sr[B2O(SO4)3] and a novel lead borosulfate Pb[B2O(SO4)3] were obtained by solvothermal reaction of the respective anhydrous metal chlorides MCl2 (M = Sr, Pb) with H[B(HSO4)4] at 300 °C. The crystal structure of Sr[B2O(SO4)3] [Pnma, Z = 4, a = 1657.38(27) pm, b = 1203.68(19) pm, c = 439.484(8) pm] is isotypic with Ba[B2O(SO4)3] and consists of chains, built up by three membered rings of two borate tetrahedra and a sulfate tetrahedron. These rings are further connected via corner‐sharing sulfate tetrahedra and hence can be classified as loop branched zweier double chains. Pb[B2O(SO4)3] crystallizes in a new structure type [P21/m, Z = 2, a = 440.00(2) pm, b = 1210.19(5) pm, c = 860.43(4) pm, β = 103.587(2) °] closely related to Sr[B2O(SO4)3]. Both structures share the common supergroup Pnmm and basically differ by the orientation of adjacent anionic chains. The coordination surrounding of Pb2+ indicates a lone pair activity and DFT calculations confirmed a weak polarizability. Moreover, the compounds were characterized by electrostatic calculations, vibrational spectroscopy and thermal analysis and broaden the structural and chemical diversity of borosulfates.

Synthesis and Characterization of the Chain Borosulfates (NH4)3[B(SO4)3] and Sr[B2(SO4)4]

“…The structure comprises one dimensional chains of alternating corner sharing borate and sulfate tetrahedra running parallel to the (001) direction (Figure ). Thus, Loewenstein's rule is obeyed in contrast to our previously reported Sr[B 2 O(SO 4 ) 3 ] . Each borate tetrahedron is connected to four adjacent sulfate tetrahedra, whereas the sulfate tetrahedra itself are connected to two adjacent borate tetrahedra.…”

“…However, for ammonium which chemically behaves very similar to potassium, only NH 4 [B(SO 4 ) 2 ] and NH 4 [B(S 2 O 7 ) 2 ] are known . Expanding research from alkali metal borosulfates towards the slightly more acidic alkaline earth metal borosulfates yielded α‐ and β‐Mg 4 [B 2 O(SO 4 ) 6 ], M [B 2 (SO 4 ) 4 ] ( M = Mg, Ca), and M [B 2 O(SO 4 ) 3 ] ( M = Sr, Ba) , . Herein, especially strontium and barium compounds are of interest, since they are promising candidates as host structure for doping with divalent europium.…”

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

“…However, also B‐O‐B [8d, 9] and S‐O‐S [8a, c, h] bridges can occur. Hitherto, borosulfates were synthesized with anionic [8, 9b–d] and even with uncharged [9a] tetrahedral networks. 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] .…”

The UV-phosphor strontium fluorooxoborate Sr[B5O7F3]:Eu

“…In the course of our systematic investigations of the broad field of silicate-analogous materials [1][2][3] we also came across compounds comprising BO 3 F tetrahedra, i.e. fluorooxoborates; systems generated through the formal addition of fluoride anions to boron compounds comprising BO 3 triangles are of interest in applications as host materials for luminescence or as NLO materials [4][5][6].…”