Synthesis-Controlled Polymorphism and Optical Properties of Phyllosilicate-Analogous Borosulfates M[B₂ (SO₄ )₄ ] (M=Mg, Co).

ABSTRACT: Increased synthetic control in borosulfate chemistry leads to the access of various new compounds. Herein, the polymorphism of phyllosilicate-analogous borosulfates is unraveled by adjusting the oleum (65 % SO₃ ) content. The new polymorphs β-Mg[B₂ (SO₄ )₄ ] and α-Co[B₂ (SO₄ )₄ ] both consist of similar layers of alternating borate and sulfate tetrahedra, but differ in the position of octahedrally coordinated cations. The α-modification comprises cations between the layers, whereas in the β-modification cations are embedded within the layers. With this new synthetic approach, phase-pure compounds of the respective polymorphs α-Mg[B₂ (SO₄ )₄ ] and β-Co[B₂ (SO₄

SUBMITTER: Netzsch P 

PROVIDER: S-EPMC7756226 | biostudies-literature | 2020 Nov

REPOSITORIES: biostudies-literature