Synthesis and crystal structure of new double mercury silver phosphide iodide Hg12Ag41P88I41

Abstract

New double mercury silver phosphide iodide Hg 12 Ag 41 P 88 I 41 (1) was synthesized and its crystal structure was established. Compound 1 crystallizes in the cubic system. The character istic feature of the crystal structure 1 is the presence of the anionic cage clusters P 11 3-, which have been previously found in alkali metal compounds only. The well ordered P 11 3-clusters form a system of polyhedra, which encapsulate various disordered α AgI type fragments.Key words: double mercury silver phosphide iodide, synthesis, crystal structure, phospho rus cluster, disorder, energy dispersive X ray analysis.The tendency of phosphorus to form homonuclear bonds is responsible for the existence of numerous phos phides with various stoichiometries and structures. 1 Both discrete phosphorus clusters and one , two , and three dimensional infinite fragments are known. Finite frag ments, for example, such chain anions as P 3 5-, P 4 6-, and P 5 7-, cyclic anions, for example, P 4 4-and P 6 6-, and the cage anions P 7 3-, P 10 6-, and P 11 3-belong to discrete clusters. The cage clusters are of interest because they are, in essence, systems of fused rings, but they form cages rather than polymeric fragments, such as layers or frame works. The adamantane like cluster P 10 6-is unique, is not present in binary phosphides, and was found only in mixed phosphides Cu 4 SnP 10 (see Ref. 2) and Au 3 SnCuP 10 . 3 The most abundant are the P 7 3-clusters, which were found in phosphides with the compositions M 3 P 7 (for alkali metals) 1,4,5 and M 3 P 14 (for Sr and Ba) 6,7 and in the Ba 2 P 7 Cl compound. 8 Oligomeric and polymeric moieties based on the P 7 3-cage clusters were also documented. 1,9,10 The P 11 3-cage clusters do not form polymeric fragments and were found only in alkali metal compounds, for ex ample, in phosphides with the composition M 3 P 11 . 1,11,12 Compounds, in which the P 11 3-clusters are stabilized by the coordination of alkali metal atoms to large organic ligands, which prevent the phosphorus atoms from inter acting directly with alkali metal atoms and forming sim pler structures, were also documented. The Cs 3 (en) 3 P 11 compound 13 can be given as an example of such com pounds.In the present study, we report the synthesis and the crystal structure of new double mercury silver phosphide iodide Hg 12 Ag 41 P 88 I 41 (1), which is the first example of the presence of the phosphorus cluster P 11 3-in com pounds containing no alkali metals. Results and DiscussionCompound 1 is dark red in color and is stable to atmo spheric moisture. It was synthesized by the conventional ampoule techniques. To optimize the conditions of the preparation of a single phase sample, we varied the an nealing temperature (400-650 °C) and the duration of heating (0.5-24 h) and cooling (quenching, the switched off furnace mode, 5 deg h -1 ) and used different starting reagents (HgI 2 , Hg 2 I 2 , AgI, Hg, Ag, and P). A single phase sample was prepared by rapid heating of a mixture with the composition 41AgI : 12Hg : 88P to 500 °C and a...

Unprecedented ∞1(P103−) band anion in the crystal structure of HgAg6P20I2

“…Hence, the title compound provides one more example of the stabilization of rare and unique phosphorus polyanions by preferable linkage of differently bonded phosphorus atoms to differently charged cations having the same coordination. The similar situation was described for some other silver mercury phosphide halides, Hg 4 Ag 5 P 8 Cl 5 , Hg 12 Ag 41 P 88 I 41 , and Hg 7 Ag 2 P 8 I 6 (Br 6 ) [6,8,9]. It should be noted that in all earlier known silver and mercury pnictide halides the coordination of silver and mercury atoms is linear, made of two phosphorus atoms, with halide atoms providing the second coordination sphere.…”