The Synthesis and Crystal Structure of Er₂（His）₄（H₂O）₈（ClO₄）₁₀（H₂O）₄

The title complex of Er₂（His）₄（H₂O）₈（ClO₄）₁₀（H₂O）₄ has been synthesized. Its IR spectra from 4000 to 400 cm^-1has been measured. The molecular and crystal structure has been determined by four-circle X-ray diffraction. The crystal is monoclinic with space P1. The unit cell parameters are as follows: a= 8.294（1）Å, b=10.981（3）Å, c=11.934（3）Å, β=107.04（2）°. Possitional and anisotropic thermal parameters have been corrected by least square method and final deflation R is 0.0821, The two Er ions in Er₂（His）₄（H₂O）₈¹⁰⁺are connected with four bridging carboxyl groups. Each pair of the carboxyl groups are coplanar with the two Er ions and the dihedral angle between the two plane is 91.9°. The N atoms of amino group and the N atoms of imidazole rings are not bound to Er ions in this dinuclear complex. There are four water moleculers which are coordinated to each Er ion of the binuclear. Therefore, there are eight oxygen atoms coordinated to each Er ions, Assuming a square antiprism arrangement.