From WCl₆ to WCl₂: Properties of Intermediate Fe–W–Cl Phases

Abstract

Phenomenological studies of WCl6 reduction with transition metal powders M = Mn, Fe, and Co have been recently reported. These reactions involve a series of reductive intercalation steps of M atoms into layered tungsten chloride arrangements, followed by exsolution of MCl2. In the series M = Fe, the presence of divalent iron is evidenced for Fe(x)WCl6, FeW2Cl10, Fe2W2Cl10, and (Fe,W)Cl2 by Mössbauer spectroscopy. Magnetic properties are reported. Bonding characteristics between tungsten atoms in edge-sharing [W2Cl10](n-) bioctahedra reveal that a double bond can be addressed to FeW2Cl10. A similar situation appears for Fe2W2Cl10, due to the localized and thus nonbonding character of the two electrons in the δ orbitals of this compound.

Snap‐Shots of a Reduction Pathway: The Reaction of WCl6 with Copper Powder

“…Recently, it has been shown that the bioctahedral [W 2 Cl 10 ] n – unit can feature various bonding situations by adopting electrons into W–W bonding energy levels. Bonding and antibonding interactions between the three t 2g d‐orbitals in the bioctahedral [W 2 Cl 10 ] n – ion can be represented by a molecular orbital (MO) scheme following the order of σ < π < δ < δ* < π* < σ* levels with increasing energy …”

“…A study of the electronic situation of the W–W bonding within edge‐sharing bioctahedra was reported for FeW 2 Cl 10 and Fe 2 W 2 Cl 10 . The [W 2 Cl 10 ] unit in FeW 2 Cl 10 is in the oxidation state 2–, while in Fe 2 W 2 Cl 10 the [W 2 Cl 10 ] unit has the oxidation state 4–, as has been confirmed through the presence of Fe 2+ by Mössbauer spectroscopy.…”

“…Crystal structures of compounds appearing in these systems were refined by means of single‐crystal and powder X‐ray diffraction. More extensive studies were performed for compounds appearing in the Fe/W/Cl system, including electronic structure calculations, magnetic measurements, energy‐dispersive X‐ray spectroscopy (EDX) and Mössbauer spectroscopy …”

Synthesis, Structure, and Electronic Properties of Sn9O5Cl4(CN2)2

“…The thermal scanning of chemical reactions can be a powerful method for the discovery of new compounds when compared to the classical explorative synthesis, where a mixture of solids is reacted at an intuitively selected temperature. The potential of the thermal scanning method has been demonstrated by the identification of more than 20 binary W–I compounds, by solid-state metathesis (SSM) reactions and by scanning a series of reduction reactions of WCl 6 to detect numerous compounds, for example, in the Pb–W–Cl, Co–W–Cl, Fe–W–Cl, and Cu–W–Cl systems. SSM reactions have been successfully employed for the development of metal compounds of nitridoborates, − cyanurates, and carbodiimides.…”

PO23– and AsO3–: Pnictogenide Ligands in the Highly Charged Re4 Cluster Anions [{Re4(PO)3(PO2)}(CN)12]8–, [{Re4As2(AsO)2}(CN)12]8–, and [{Re4(AsO)4}(CN)12]8–

“…The use of transition metal chlorides − and bromides , for the synthesis of cluster compounds is quite typical, while iodides are only rarely used. Recent data for tungsten and rhenium iodides have, however, demonstrated a significant difference of the iodides from the corresponding chlorides and bromides in metal cluster synthesis reactions.…”