Crystal growth and X-ray investigation of a layered bismuth oxide sulfate in the CoSO₄ —Bi₂O₃ system

Abstract

A bismuth oxide sulfate, [Bi γ _ *Οο χ Ο] 2 (S0 4 ) ιx ο. 14 < * < ο. 18> was prepared by interacting C0SO4 with Bi 2 0 3 . Single crystals were obtained and investigated by X-ray diffraction. They are monoclinic, CI, a = 5.615 (3) Ä, b = 5.535(2) Ä, c = 8.080(2) A, /? = 108.97(5)°, Ζ = 2,244 measured reflexions: R = 0.079. The structure consists of continuous [Bi, _ x Co x O]" fluorite-like layers separated by S0 4~ anions. It shows close structural similarity to the mineral nadorite, PbSb0 2 Cl and the already reported [Bi 2 Co0 3 ]S0 4 (Fanariotis and Rentzeperis, 1987).

Revised Bi/M Layered Oxo-Sulfate (M = Co, Cu): A Structural and Magnetic Study

“…Single crystals of II were originally prepared by heating in Pyrex-evacuated tubes a mixture of Bi 2 O(SO 4 ) and CuO in a Bi/Cu ratio = 2:1 (see ref ). In our study, green bulk crystals were grown in the melt of a mixture of Bi 2 O 3 + CuO + (NH 4 ) 2 SO 4 (molar ratio = 1:1:2).…”

“…As far as we know, in addition to a handful of bismuth oxo-sulfates such as the 2D Bi 26 O 27 (SO 4 ) 12 built up of fluorite-like steps only rare cases of mixed Bi/M oxo-sulfates are known. For instance, [Bi 1– x Co x O] 2 (SO 4 ) 1– x , where 0.14 ≤ x ≤ 0.18, adopts a Sillén-X1 phase. , More intriguing cases involve pleated oxo-centered layers found in both [Bi 2 CoO 3 ](SO 4 ) (Figure e) and [Bi 13.33 Cu 2 O 16 ](SO 4 ) 6 with segregation of the transition metals within the layers. However, in both cases, the examination of reported crystal structures highlights strong SO 4 disorder.…”