Bd. James et al., THE UNSOLVATED PENTACHLOROFERRATE(III) ION - X-RAY CRYSTAL-STRUCTURE AND LOW-TEMPERATURE MAGNETISM OF TETRAMETHYLPIPERAZINIUM PENTACHLOROFERRATE(III), Inorganic chemistry, 34(8), 1995, pp. 2054-2057
Single-crystal X-ray diffraction study of the title compound, C8H20Cl5
N2Fe, indicates crystallization in the monoclinic space group C2/c, Z
= 4, with unit cell parameters a = 15.56(1) Angstrom, b = 8.876(3) Ang
strom, c 12.487(6) Angstrom, and beta = 115.61(6)degrees, with a nearl
y ideal five-coordinate trigonal bipyramidal [FeCl5](2-) species in an
ionic crystal lattice. A combination of Fe-57 Mossbauer spectroscopy
and a.c. susceptometry confirms long-range magnetic order between 6 an
d 7 K with a 3-D antiferromagnetic ground state.