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Title: New rubidium zinc hydrogen phosphate, Rb{sub 2}Zn{sub 2}(HPO{sub 4}){sub 3}: Synthesis, crystal structure, and {sup 31}P single-crystal NMR

Journal Article · · Inorganic Chemistry
DOI:https://doi.org/10.1021/ic9906757· OSTI ID:20075872

A new rubidium zinc hydrogen phosphate, Rb{sub 2}Zn{sub 2}(HPO{sub 4}){sub 3}, is prepared by an unusual method utilizing long nucleation times. This material is crystallized from a gel with an initial composition of 1.0 ZnO/0.94 P{sub 2}O{sub 5}/0.96 Rb{sub 2}O/0.04 Li{sub 2}O/41 H{sub 2}O, while the phosphate concentration equals 1.6 M and pH = 3.5. The gel is placed in a sealed Pyrex flask at 52 C, and after 4.5 months crystallization of Rb{sub 2}Zn{sub 2}(HPO{sub 4}){sub 3} is noticed. This new crystalline compound has a three-dimensional framework structure built from spiral chains of alternating PO{sub 4} and ZnO{sub 4} tetrahedra connected pairwise and assembled by other PO{sub 4} tetrahedra, rubidium ions, and hydrogen bonds. The two rubidium ions, Rb(1) and Rb(2), have an exceptionally low number of oxygen contacts in the first coordination sphere, five and seven, respectively. Crystal data: monoclinic, P2{sub 1}/c (no. 14), a = 12.5880(4), b = 12.7170(8), c = 7.5827(8) {angstrom}, {beta} = 96.100(1){degree}, Z = 4. A single-crystal {sup 31}P NMR investigation of Rb{sub 2}Zn{sub 2}(HPO{sub 4}){sub 3} was performed employing a two-axis goniometer probe and reveals the presence of three chemically and six magnetically nonequivalent phosphorus sites, in accordance with the crystal structure. {sup 31}P chemical shielding anisotropies and isotropic chemical shifts ({minus}3.3(3), {minus}2.6(3), and 2.0(3) ppm) have been determined for the three phosphorus sites.

Research Organization:
Univ. of Southern Denmark, Odense (DK)
OSTI ID:
20075872
Journal Information:
Inorganic Chemistry, Vol. 39, Issue 10; Other Information: PBD: 15 May 2000; ISSN 0020-1669
Country of Publication:
United States
Language:
English