The First Open-Framework Cadmium Phosphate, K4[Cd3(HPO4)4(H2PO4)2], with a Layered Structure

✍ Scribed by K. Jayaraman; R. Vaidhyanathan; Srinivasan Natarajan; C.N.R. Rao

• Publisher: Elsevier Science
• Year: 2001
• Tongue: English
• Weight: 463 KB
• Volume: 162
• Category: Article
• ISSN: 0022-4596
• DOI: 10.1006/jssc.2001.9228

✦ Synopsis

A layered cadmium phosphate of the formula K 4 [Cd 3 (HPO 4 ) 4 (H 2 PO 4 ) 2 ], I, containing six-membered apertures, constituting the 5rst example of an open-framework cadmium phosphate, has been synthesized under hydrothermal conditions. Crystal data: monoclinic, P2 1 /n (No. 14), a ‫؍‬ 9.0698( 3), b ‫؍‬ 6.7341(3), and c ‫؍‬ 18.2663(7) A > , ‫؍‬ 93.092(1)3, V ‫؍‬ 1114.03 A > 3 , Z ‫؍‬ 4. The structure consists of a network of CdO 6 octahedra and PO 3 (OH) and PO 2 (OH) 2 tetrahedra forming a spiro unit, which are connected through Cd 2 O 2 two-membered rings forming one-dimensional chains. The chains are further connected forming two-dimensional macroanionic layers with six-membered apertures possessing hanging phosphate units on either side of the layer. The layers are stabilized by strong hydrogen bond interactions between the terminal P+OH groups forming pseudo channels in which the charge-compensating extraframework K ؉ ions are located. The presence of the spiro unit and the in5nite one-dimensional Cd+O+Cd chains, along with the hanging phosphates are noteworthy structural features.