Crystal chemistry and topology of Rb-MIII molybdates (M = Fe,Sc,In) and triclinic Rb2Mo4O13: novel building blocks, decorated chains and layers

Maria Wierzbicka-Wieczorek, Ekkehart Tillmanns, Uwe Kolitsch

Veröffentlichungen: Beitrag in FachzeitschriftArtikelPeer Reviewed

Abstract

Four different rubidium metal molybdates and Rb2Mo4O13 have been synthesised by flux growth and their crystal structures were determined from single-crystal X-ray diffraction data. The compound Rb5Fe(MoO4)4 represents a novel and unusual structure type based on isolated Fe2Mo8O22 building blocks (with a central Fe2O8 dimer composed two edge-sharing square pyramids in an up-down arrangement) linked by Rb+ cations (Cmca, a = 18.355(4), b = 10.487(2), c = 39.303(3) Å, V = 7566(4) Å3, R(F) = 3.46%, Z = 16). Rb5In(MoO4)4 is characterised by a decorated kröhnkite-like octahedral-tetrahedral chain structure (P2/c, a = 11.391(2), b = 7.983(2), c = 11.100(2) Å, ß = 113.74(3)°, V = 924.0(3) Å3, R(F) = 2.27%, Z = 2). It is isotypic with Rb5Er(MoO4)4. The two compounds RbFe(MoO4)2 and RbSc(MoO4)2, both crystallise in KAl(MoO4)2-type structures in space group P-3m1, with a = 5.673(1)/5.789(1), c = 7.495(2)/7.578(2) Å, V = 208.89(8)/219.93(8) Å3, R(F) = 1.69/1.26%, respectively, Z = 1. The simple Rb molybdate Rb2Mo4O13 is triclinic and isotypic with K2Mo4O13 and the triclinic modification of (NH4)2Mo4O13. It has space group P-1, with a = 8.259(2), b = 8.402(2), c = 10.274(2) Å, a = 104.56(3) ß = 106.41(3), ? = 109.90(3)°, V = 593.4(2) Å3, R(F) = 2.20%, Z = 2. The different connectivities within the structures and the role of the Rb atoms are discussed. The topologies and relative stabilities of M2Mo4O13 (M = (NH4), K, Rb, Cs, Tl) compounds and their structure types are briefly reviewed.
OriginalspracheEnglisch
Seiten (von - bis)151-162
Seitenumfang12
FachzeitschriftZeitschrift für Kristallographie : international journal for structural, physical, and chemical aspects of crystalline materials
Jahrgang224
Ausgabenummer3
PublikationsstatusVeröffentlicht - 2009

ÖFOS 2012

  • 105113 Kristallographie

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