Hydrothermal synthesis and crystal structure study of two novel 3-D mellitates {Nd 2[C 6(COO) 6] (H 2O) 6} and {Ho 2[C 6(COO) 6](H 2O) 6}

• Published in: Journal of rare earths 2008-12, Vol.26 (6), p.800-803
• Main Authors: TANG, Xiaoyong, YUE, Shantang, LI, Ping, WANG, Ning, LIU, Yingliang
• Format: Article
• Language: English
• Subjects: crystal structure; hydrothermal synthesis; isostructural; mellitic acid; rare earths
• ISSN: 1002-0721; 2509-4963
• DOI: 10.1016/S1002-0721(09)60009-0

Two novel 3-D coordination compounds, Nd 2[C 6(COO) 6](H 2O) 6 ( 1) and Ho 2[C 6(COO) 6](H 2O) 6 ( 2), were hydrothermally synthesized from mellitic acid and neodymium perchlorate (or holmium perchlorate) in the alkaline aqueous solution and characterized with elemental analysis, TG, IR spectrum, and single crystal X-ray diffraction. The two compounds were isostructural and crystallized in the orthorhombic system, space group Pnnm, with a=1.3531 (4) nm, b=0.6687 (2) nm, c=1.0224(3) nm, V=0.92523(5) nm 3, Z=4, D=2.630 g/cm 3, F(000)=696.0, Goof=1.052. Final R indices [ I >2Σ( I)]: R 1=0.0195, wR 2=0.0382 for 1; a=1.3411(2) nm, b=0.6586(1) nm, c=1.0116(2) nm, V=0.8935(3) nm 3, Z=4, D=2.877 g/cm 3, F(000)=724.0, Goof=1.061. Final R indices [ I >2Σ( I)]: R 1=0.0200, wR 2=0.0479 for 2. In the two compounds 1 and 2, the mellitic acid ligand, in which all the carboxylate groups were deprotonated, had only one kind of coordination mode to bridge metal ions to form four-connected three-dimensional diamondiod networks.