The First Open-Framework Cadmium Phosphate, $K_4[Cd_3(HPO_4)_4(H_2PO_4)_2]$, with a Layered Structure

Jayaraman, K and Vaidhyanathan, R and Natarajan, Srinivasan and Rao, CNR (2001) The First Open-Framework Cadmium Phosphate, $K_4[Cd_3(HPO_4)_4(H_2PO_4)_2]$, with a Layered Structure. In: Journal of Solid State Chemistry, 162 (2). pp. 188-194.

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Abstract

A layered cadmium phosphate of the formula $K_4[(Cd_3(HPO_4)_4(H_2PO_4)_2]$, I, containing six-membered apertures, constituting the first 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) \AA, $\beta =93.092(1)^0$, $V=1114.03 \AA^3$, 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 $Cd_2O_2$ 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 infinite one-dimensional Cd–O–Cd chains, along with the hanging phosphates are noteworthy structural features.

Item Type: Journal Article Copyright of this article belongs to Elsevier. Spiro units;one-dimensional chains;framework;cadmium phosphate. Division of Chemical Sciences > Solid State & Structural Chemistry Unit 12 Aug 2008 19 Sep 2010 04:49 http://eprints.iisc.ernet.in/id/eprint/15536