Single crystals of Co4Fe3.33(VO4)6 and Mn3Fe4(VO4)6 were grown from equivalent CoO/Fe2O3/V2O5 and MnO/Fe2O3/V2O5 melts, respectively. The former crystallizes in the orthorhombic space group Pnma with parameters a = 4.965(1) Å, b = 10.211(1) Å, c = 17.188(3) Å, and Z = 2 and is a homeotype of such catalysts as Mg2.5VMoO8. The latter crystallizes in the triclinic space group P1̄ with parameters a = 6.703(2) Å, b = 8.137(1) Å, c = 9.801(2) Å, α = 105.56(1)°, β = 105.58(2)°, γ = 102.35(1)°, and Z = 1 and is a homeotype of β-Cu3Fe4(VO4)6, the low-pressure form of α-Cu3Fe4(VO4)6. The cobalt analogue deviates in stoichiometry from the reactant melt to form the more dense α-Cu3Fe4(VO4)6 structure type comprised of partially occupied face-sharing octahedral and trigonal prismatic coordination sites.
ASJC Scopus subject areas
- Inorganic Chemistry