Crystal structure of Ca₂Zn₂(V₄O₁₄) and Pb₂Cd₂(V₃O₁₀)(VO₄) double vanadates

Abstract

Polycrystalline samples of Ca2Zn2(V4O14) (I) and Pb2Cd2(V3O10)(VO4) (II) were synthesized using the nitrate–citrate method (I) and conventional solid state reaction (II). The structural refinement based on X-ray powder diffraction data showed that the crystal structure of (I) is characterized by monoclinic symmetry with unit-cell parameters a = 6.8044(1) Å, b = 14.4876(3) Å, c = 11.2367(2) Å, β = 99.647(1)° [space group P21/c (No. 14), Z = 4], and the crystal structure of (II) is triclinic with unit-cell parameters a = 7.03813(6) Å, b = 12.9085(1) Å, c = 6.99961(5) Å, α = 90.7265(5)°, β = 96.3789(5)°, γ = 94.9530(6)°, V = 629.470(8) Å3 [space group P$\bar 1$ (No. 2), Z = 2].

Antiferromagnetic order of ferromagnetically coupled dimers in the double pyrovanadate CaCoV$_2$O$_7$

“…Closely related to the pyrovanadates M 2 V 2 O 7 , there exists a class of materials known as the double pyrovanadates with the chemical formula M M ′ V 2 O 7 , where M and M ′ are typically (but not limited to) the nonmagnetic alkaline-earth and magnetic transition-metal ions, respectively. Crystal structure of the double pyrovanadates has been extensively studied in the past [35,36]. It has been known that introduction of nonmagnetic M ions results in deformation and/or termination of magnetic lattice in various manner.…”