Publication Date:
2013-08-17
Description:
Re VII O 2 (PO 4 ) and (Re VII 2 O 5 )Si o 2 [Si t 2 O(PO 4 ) 6 ] were obtained from Re 2 O 7 and P 4 O 10 in sealed silica tubes (250 ≤ ϑ ≤ 400 °C). The crystal structures were solved and refined from X-ray single crystal data (Re VII O 2 (PO 4 ): C 2/ c , Z = 24, a = 14.403(1) Å, b = 8.414(1) Å, c = 20.647(3) Å, β = 93.165(8)°, T = 123 K, 10352 ind. refl., 218 variables, 24 atoms in asymmetric unit, R 1 = 0.041, wR 2 = 0.106; (Re VII 2 O 5 )Si o 2 [Si t 2 O(PO 4 ) 6 ]: P , Z = 1, a = 7.8589(3) Å, b = 7.8609(3) Å, c = 10.8311(4) Å, α = 85.312(2)°, β = 73.078(2)°, γ = 60.075(2)°, T = 298 K, 2551 ind. reflections, 174 variables, 22 atoms in asymmetric unit, R 1 = 0.078, wR 2 = 0.208). The complex crystal structure of ReO 2 (PO 4 ) can be derived from the ReO 3 structure type. The crystal structure of the silicophosphate consists of distorted [Re 2 O 11 ] dioctahedra (1.69 Å ≤ d (Re–O) ≤ 2.08 Å), [Si IV O 6 ] octahedra, and [Si t 2 O(PO 4 ) 6 ] 12– heteropolyanions. In ReO 2 (PO 4 ) monomeric perrhenyl ions (ReO 2 ) 3+ (∠(O t ,Re, O t ) ≈ 101.5°) are formed. The silicophosphate (Re 2 O 5 )Si o 2 [Si t 2 O(PO 4 ) 6 ] contains dinuclear (Re 2 O 5 ) 4+ cations. 31 P-MAS-NMR studies on ReO 2 (PO 4 ) are in accordance with three independent sites of phosphorus. The results of 31 P- and 29 Si-MAS-NMR studies on (Re 2 O 5 )Si o 2 [Si t 2 O(PO 4 ) 6 ] are in agreement with three crystallographically independent sites for phosphorus and two sites for silicon.
Print ISSN:
0044-2313
Electronic ISSN:
1521-3749
Topics:
Chemistry and Pharmacology
Permalink