Chloride Derivatives of Lanthanide Ortho‐Oxomolybdates: 2. The Unique Crystal Structure of NdCl[MoO4] in the LnCl[MoO4] Series

Abstract

AbstractThe reaction of Nd2O3, NdCl3, and MoO3 in a molar ratio of 1:1:3 leads to a phase‐pure product, consisiting of bulky, pale violet single crystals of NdCl[MoO4]. The title compound crystallises orthorhombically in space group Pbam with four formula units per unit cell (a = 1991.61(9) pm, b = 693.79(3) pm, c = 742.53(3) pm) and is therefore not isotypic with the so far observed phases within the LnCl[MoO4] series (Ln = La–Lu). The crystal structure contains two crystallographically distinguishable tetrahedral [MoO4]2– anions, which are surrounded by five Nd3+ cations each. Four of them represent terminal ligands, the fifth one coordinates through an edge. There are also two crystallographically different Nd3+ cations in the structure, which both show almost the same coordination environment, namely a distorted trigonal dodecahedron, consisting of two Cl– and six O2– anions. The structure is built up by chains of oxide‐edge sharing [NdCl2O6]11– polyhedra, which form double chains through a Cl1···Cl1 bridge at the dodecahedron around (Nd1)3+. These double chains are connected to four adjacent double chains by Cl2 vertices of the (Nd2)3+ polyhedron. Finally, the Mo6+ cations come to lie in tetrahedral oxygen voids of this three‐dimensional network.