Polymorphism and optical, magnetic and thermal properties of the either phyllo- or inosilicate-analogous borosulfate Cu[B2(SO4)4]. Issue 8 (9th February 2022)

• Record Type: Journal Article
• Authors: Hämmer, Matthias; Pielnhofer, Florian; Janka, Oliver; Takahashi, Hirotaka; Gross, Peter; Pöttgen, Rainer; Höppe, Henning A.
• Is Part Of: Dalton transactions. Volume 51:Issue 8(2022)
• Page Start: 3104
• Page End: 3115
• Publication Date: 2022-02-09
• Subjects: Chemistry, Inorganic -- Periodicals; Chemistry, Physical and theoretical -- Periodicals; Chemistry, Inorganic -- Periodicals; 546.05
• DOI: 10.1039/d1dt04090a
• Languages: English
• ISSNs: 1477-9226

Abstract

Abstract : Reaction of Cu2 [(OH)2 CO3 ], H3 BO3 and oleum yields either inosilicate-analogous α-Cu[B2 (SO4 )4 ] or the new phyllosilicate-analogous β-Cu[B2 (SO4 )4 ], both subject to Jahn–Teller distortion; two polymorphs of Cu(HSO4 )2 and Cu[S2 O7 ] are also reported. Abstract : Two polymorphs of the borosulfate Cu[B2 (SO4 )4 ] can be selectively prepared by solvothermal syntheses. The crystal structures of inosilicate-analogous α-Cu[B2 (SO4 )4 ] ( P 1̄, no. 2, a = 5.2636(2), b = 7.1449(2), c = 7.9352(2) Å, α = 73.698(2)°, β = 70.737(2)°, γ = 86.677(2)°, 65 parameters, R Bragg = 0.0052) and the new phyllosilicate-analogous polymorph β-Cu[B2 (SO4 )4 ] ( P 21 / n, no. 14, a = 7.712(3), b = 8.149(3), c = 9.092(3) Å, β = 111.22(1)°, 3829 independent reflections, 106 parameters, wR 2 = 0.054) are discussed. Further, the optical, magnetic and thermal properties of both polymorphs are investigated with focus on the role of the Cu 2+ cation and its Jahn–Teller effect. The findings are confirmed by DFT calculations yielding insights in the stability of the synthesised polymorphs as well as a predicted γ-modification. Additionally, the crystal structures of two polymorphs of copper hydrogensulfate Cu(HSO4 )2 -I ( P 21 / n, no. 14, a = 4.7530(2), b = 8.5325(4), c = 7.3719(3) Å, β = 100.063(1)°, 1063 independent reflections, 55 parameters, wR 2 = 0.052) and Cu(HSO4 )2 -II ( P 1̄, no. 2, a = 4.79.88(8), b = 7.857(1), c = 8.057(1) Å, α = 77.86(1)°, β = 87.02(1)°, γ = 89.82(1)°, 1044 independent reflections, 109 parameters, wR 2 = 0.132) as well as that of Cu[S2 O7 ] ( C 2/ c, no. 15, a = 6.6341(4), b = 8.7302(5), c = 9.0555(8) Å, β = 104.763(3)°, 1117 independent reflections, 48 parameters, wR 2 = 0.049) are presented and the cyclosilicate-analogous borosulfate Cu[B(SO4 )2 (HSO4 )] is fully characterised with respect to its optical and thermal properties.