Hydrothermal Syntheses, Structures, and Magnetic Properties of the U(IV) Fluorides (C{sub 5}H{sub 14}N{sub 2}){sub 2}U{sub 2}F{sub 12} {center_dot} 5H{sub 2}O and (NH{sub 4}){sub 7}U{sub 6}F{sub 31}
The U(IV) fluorides (C{sub 5}H{sub 14}N{sub 2}){sub 2}U{sub 2}F{sub 12}{center_dot}5H{sub 2}O and (NH{sub 4}){sub 7}U{sub 6}F{sub 31} have been prepared from the reaction of UO{sub 3} with HF and homopiperazine (C{sub 5}H{sub 12}N{sub 2}) at 180 C in aqueous media. AU1-2 contains dodecahedral UF{sub 8} units that share two edges to form {sup 1}{sub {infinity}}[UF{sub 4}F{sub 4/2}] one-dimensional chains. The fluoride ligands form hydrogen bonds with the diprotonated homopiperazinium cations to yield channels running down the a axis that contain occluded water molecules. (NH{sub 4}){sub 7}U{sub 6}F{sub 31} is isostructural with Na{sub 7}Zr{sub 6}F{sub 31}, forming a three-dimensional network consisting of edge- and corner-sharing UF{sub 8} square antiprisms that create cubooctahedral clusters and small intersecting channels. A disordered fluoride anion resides in the cubooctahedral cavities and the ammonium cations partially fill the channels. AU1-2 and (NH{sub 4}){sub 7}U{sub 6}F{sub 31} display similar magnetic behavior with {mu}{sub eff} (300 K)=3.05 and 3.03 {mu}{sub B}/U(IV) and {theta}={minus}97 and {minus}126 K, respectively. Crystallographic data: AU1-2, monoclinic, space group P2{sub 1}/n, a=6.545(3) {angstrom}, b=19.90(1) {angstrom}, c=19.07(1) {angstrom}, {beta}=98.89(4){degree}, Z=4, {lambda}=0.71073 {angstrom}, R(F)=0.0395 for 293 parameters with 3282 reflections with I>2{sigma}(I); (NH{sub 4}){sub 7}U{sub 6}F{sub 31}, rhombohedral, space group R{bar 3}, a=15.371(3) {angstrom}, c=10.791(3) {angstrom}, Z=3, {lambda}=0.71073 {angstrom}, R(F)=0.0242 for 82 parameters with 841 reflections with I>2{sigma}(I).
- Research Organization:
- Department of Chemistry, Auburn University, Auburn, Alabama (US); Department of Chemistry, University of Alberta, Edmonton, Alberta (CA)
- Sponsoring Organization:
- NASA (Alabama Space Grant Consortium) (US); NASA-EPSCoR (Experimental Program to Stimulate Competitive Research) (US); Auburn University (US); NSERC (CA); University of Alberta (CA)
- OSTI ID:
- 784366
- Journal Information:
- Journal of Solid State Chemistry, Vol. 158, Issue 1; Other Information: PBD: 1 Apr 2001; ISSN 0022-4596
- Country of Publication:
- United States
- Language:
- English
Similar Records
Synthesis and structure of [C{sub 6}H{sub 14}N{sub 2}][(UO{sub 2}){sub 4}(HPO{sub 4}){sub 2}(PO{sub 4}){sub 2}(H{sub 2}O)].H{sub 2}O: An expanded open-framework amine-bearing uranyl phosphate
Crystal structures of Li{sub 4}ZrF{sub 8} and Li{sub 3}Zr{sub 4}F{sub 19} and reinvestigation of the LiF-ZrF{sub 4} phase diagram