Hydrothermal Vanadium Fluoride Chemistry:  Four New V³⁺ Chain Structures

Abstract

An exploratory study of the hydrothermal chemistry of vanadium in HF solutions has resulted in the preparation of four new vanadium (III) fluorides with chainlike structural motifs. [NH4]2[VF5] (1) and [C2N2H10][VF5] (2) feature infinite chains of trans corner-sharing VF4F2/2 octahedra, [C4N2H6][VF5].H2O (3) has cis corner-sharing [VF4F2/2]infinity chains, and [C10N2H8][VF3] (4) has trans corner-sharing [VF2F2/2]infinity chains bridged into sheets by the 4,4'-bipy linker. All four compounds exhibit antiferromagnetic behavior.

Synthesis of a d2 kagome lattice antiferromagnet, (CH3NH3)2NaV3F12

“…This synthetic method is developed based on a related methodology. 33 The crystal structure of 1-V was determined by single crystal X-ray diffraction (SCXRD) on a brown-green crystal ($0.187 mm  0.14 mm  0.124 mm, Fig. S1 †) at 300 K. 34 The lack of an obvious difference between the experimental powder X-ray diffraction (PXRD) pattern and the pattern simulated from the SCXRD structure (Fig.…”

A Nearly Ideal One-Dimensional S = 5/2 Antiferromagnet FeF3(4,4′-bpy) (4,4′-bpy =4,4′-bipyridyl) with Strong Intrachain Interactions

“…16 In VF 3 (4,4′-bpy) with S = 1/2, no obvious broad maximum is seen possibly because of low sample quality and/or paramagnetic impurity. Furthermore, it exhibits a magnetic order at 8 K. 15,16 In spite of the high T(χ max ), 1 remains paramagnetic even down to 2 K, giving T N /T(χ max ) < 0.01 (T N < 2.0 K). This reflects the excellent one-dimensionality of 1 characterized by fairly strong intrachain interaction and very small interchain interactions.…”

New Compounds and Structures in the Solid State

“…The magnetic properties of these materials reflect the anisotropic structure and show evidence of 1-dimensional antiferromagnetic coupling at relatively high temperatures but no clear indication of long-range magnetic ordering on cooling these materials to 2 K. The fluoride chemistry of V 3+ has also revealed the presence of 1-dimensional units in another series of compounds. 49 In this case the chains are composed of VF 6 octahedra linked by via corner sharing in either a cis or trans fashion depending on the counter-cation. In the case of [4,4 0 -bipyridyl][VF 3 ] the chains of trans-linked VF 6 octahedra are cross-linked by 4,4 0 -bipyridyl to give a 2-dimensional network.…”