The Crystal and Molecular Structures of Tetraethylammonium [Tetraaquatetrakis(isothiocyanato)neodymate(III) and europate(III)], [(C2H5)4N][M(NCS)4(H2O)4], (M=Nd, Eu)

The crystal and molecular structures of the title new complexes were determined by means of a single-crystal X-ray diffraction method. The crystals of the neodymium(III) complex, NdC12H28N5O4S4, F. W. 578.87, are triclinic, space group P\bar1, a=14.13(2), b=15.39(1), c=12.92(1) A, α=106.81(8), β=114.70(9), γ=90.09(10)°, U=2418(5) A3, Z=4, Dm=1.57(3), Dx=1.59 g cm−3, μ(MoKα)=25.22 cm−1. The isomorphous europium(III) complex was also obtained: a=14.069(9), b=15.328(9), c=12.865(9) A, α=106.98(5), β=114.57(5), γ=90.07(6)°, U=2390(3) A3, Dm=1.60(3), Dx=1.63 g cm−3, μ(Mo Kα)=30.04 cm−1. Two crystallographically independent neodymium(III) atoms in a unit cell have approximately the same coordination geometry: square antiprism 4O,4N-octa-coodination. A pair of the O atoms as well as N atoms are in cis positions on the top square and in trans positions on the bottom square of each polyhedron, where the lines connecting both pairs of the N atoms on both squares are approximately parallel.