Abstract
Colorless single crystals of Gd(IO3)3 or pale pink single crystals of Er(IO3)3 have been formed
from the reaction of Gd metal with H5IO6 or Er metal with H5IO6 under hydrothermal reaction
conditions at
180 1C. The structures of both materials adopt the Bi(IO3)3 structure type. Crystallographic
data are (MoKa, l ¼ 0.71073 A˚ ): Gd(IO3)3, monoclinic, space group P21/n, a ¼ 8.7615(3)
A˚ , b ¼ 5.9081(2) A˚ , c ¼ 15.1232(6) A˚ , b ¼ 96.980(1)1, V ¼ 777.03(5) Z ¼ 4, R(F) ¼
1.68% for 119 parameters with 1930 reflections with I42s(I); Er(IO3)3, monoclinic, space
group P21/n, a ¼ 8.6885(7) A˚ , b ¼ 5.9538(5) A˚ , c ¼ 14.9664(12) A˚ , b ¼ 97.054(1)1, V ¼
768.4(1) Z ¼ 4, R(F) ¼ 2.26% for 119 parameters with 1894
reflections with I42s(I). In addition to structural studies, Gd(IO3)3, Er(IO3)3, and the
isostructural Yb(IO3)3 were also characterized by Raman spectroscopy and magnetic property
measurements. The results of the Raman studies indicated that the vibrational profiles are
adequately sensitive to distinguish between the structures of the iodates reported here and other
lanthanide iodate systems. The magnetic measurements indicate that only in Gd(IO3)3 did the 3+
lanthanide ion exhibit its full
7.9 mB Hund’s rule moment; Er3+ and Yb3+ exhibited ground state moments and gap energy scales of
8.3 mB/70 K and 3.8 mB/160 K, respectively. Er(IO3)3 exhibited extremely weak ferromagnetic
correlations (+0.4 K), while the magnetic ions in Gd(IO3)3 and Yb(IO3)3 were fully
non-interacting within the resolution of our measurements ("'0.2 K).