Crystal Structures of (Et4N)3M2F9 (M = V, Cr, Fe) determined by X-Ray Single-Crystal and Powder Diffraction: A New Structure Type for A3M2X9 Compounds

Abstract

The syntheses and X-ray structure determinations of single crystals and powders are reported for the compounds (Et 4 N) 3 M 2 F 9 (M = V 3+ , Cr 3+ , Fe 3+ ). The compounds are isostructural and represent a new structure type for A 3 M 2 X 9 compounds. They crystallize in the hexagonal space group P6 3 /m with Z = 2. Their lattice parameters are (Et 4 NStrukturbestimmung von (Et 4 N) 3 M 2 F 9 (M = V, Cr, Fe) mittels Einkristallund Pulverro È ntgendiffraktion: Ein neuer A 3 M 2 X 9 Strukturtyp Inhaltsu È bersicht. Die Verbindungen (Et 4 N) 3 M 2 F 9 (M = V 3+ , Cr 3+ , Fe 3+ ) wurden synthetisiert und ihre Kristallstrukturen aus Ro È ntgendiffraktionsmessungen an Einkristallen und Pulvern bestimmt. Alle drei Verbindungen sind isostrukturell und repra È sentieren einen neuen A 3 M 2 X 9 Strukturtyp. Sie kristallisieren in der hexagonalen Raumgruppe P6 3 /m mit Z = 2. Ihre Gitterkonstanten betragen fu È r (Et 4 N

Butterfly hysteresis and slow relaxation of the magnetization in (Et4N)3Fe2F9: manifestations of a single-molecule magnet

“…3, the mass density ρ = 1.36 g/cm 3 [15] and the Bose population factor (e (ε M S ±1 −ε M S )/kT − 1). [19] We note that (ε The magnetization data shown in Fig.…”

“…The product was characterized by X-ray powder diffraction using the struc-tural information from ref. [15]. It crystallizes in the space group P6 3 /m with the trigonal axes of the [Fe 2 F 9 ] 3− dimers parallel to the hexagonal c axis, see the inset of Fig.…”

Phonon bottleneck effect leads to observation of quantum tunneling of the magnetization and butterfly hysteresis loops in(Et4N)3Fe2Schenker1, Leuenberger2, Chaboussant3 et al. 2005Phys. Rev. BSelf Cite

“…14. The dimer symmetry is exactly C 3h with the threefold axis lying parallel to the hexagonal crystal axis c. 16 The intradimer Fe ... Fe distance is 2.907 Å. The dimer molecules are well separated from each other, leading to interdimer Fe ... Fe distances of at least 8 Å, thus making interdimer interactions extremely inefficient.…”

“…where g 0 is the spin-thermal phonon interaction parameter, ρ = 1.36 × 10 3 g/cm 3 the mass density, 16 v the sound velocity, and S mj+1 mj = (S − M j )(S + M j + 1)(2M j + 1) 2 in the quantization axis defined by H eff,x (note that H z = 0). 26 Considering only transitions between the two lowest levels, τ in can be approximated by…”

Inorganic Molybdenum Octahedral Nanosized Cluster Units, Versatile Functional Building Block for Nanoarchitectonics

“…This enhanced hydrogen uptake may be assigned to higher heat of adsorption for hydrogen in MIL-101-Mo 6 Br 8 F 6 . The highly polarized Mo-F a is explained by the steric hindrance of inner ligands that do not favor covalent interactions between Mo and F. The challenge in view of applications will consist now to tailor made fluorinated metal atom clusters with lower molecular weight than [Mo 6 Br i 8 F a 6 ] 2-' as for instance [Cr 2 F i 3 F a 3 ] 3units [113][114][115]. The latter will have two advantages: (i) chromium is lighter than molybdenum and (ii) the fluorine/metal ratio is 4.5…”