High-pressure high-temperature synthesis and crystal structure of the isotypic rare earth (RE)–thioborate–sulfides RE9[BS3]2[BS4]3S3, (RE=Dy–Lu)

Application of high-pressure high-temperature conditions (3.5 GPa at 1673 K for 5 h) to mixtures of the elements (RE:B:S=1:3:6) yielded crystalline samples of the isotypic rare earth–thioborate–sulfides RE9[BS3]2[BS4]3S3, (RE=Dy–Lu), which crystallize in space group P63 (Z=2/3) and adopt the Ce6Al3.33S14 structure type. The crystal structures were refined from X-ray powder diffraction data by applying the Rietveld method. Dy: a=9.4044(2) Å, c=5.8855(3) Å; Ho: a=9.3703(1) Å, c=5.8826(1) Å; Er: a=9.3279(12) Å, c=5.8793(8) Å; Tm: a=9.2869(3) Å, c=5.8781(3) Å; Yb: a=9.2514(5) Å, c=5.8805(6) Å; Lu: a=9.2162(3) Å, c=5.8911(3) Å. The crystal structure is characterized by the presence of two isolated complex ions [BS3]3– and [BS4]5– as well as [□(S2–)3] units.

Isotypic rare earth–thioborate–sulfides RE9[BS3]2[BS4]3S3, (RE=Dy–Lu) were prepared by application of high-pressure high-temperature conditions to mixtures of the elements. Their crystal structures are characterized by presence of the two isolated complex ions [BS3]3– and [BS4]5– as well as [□(S2–)3] units. Quantum mechanical calculations revealed the arrangement of the intrinsic vacancies.Figure optionsDownload as PowerPoint slideResearch Highlights
► Application of high-pressure high-temperature conditions to mixtures of the elements yields crystalline samples of the isotypic rare earth–thioborate–sulfides RE9[BS3]2[BS4]3S3, (RE=Dy–Lu).
► RE9[BS3]2[BS4]3S3, (RE=Dy–Lu) crystallize in space group P63 (Z=2/3) and adopt the Ce6Al3.33S14 structure type.
► The crystal structure of RE9[BS3]2[BS4]3S3, (RE=Dy–Lu) is characterized by the presence of two isolated complex ions [BS3]3– and [BS4]5– as well as [□(S2–)3] units.
► The vacancies in Lu9[BS3]2[BS4]3S3 are located at the trigonal planar coordinated boron site with preferred ordering –B2–B2–□–B2–B2–□– along [001].