Synthèse et caractérisation structurale d'un phosphate d'indium In₃P₂O₈ présentant des paires In–In

Abstract

The crystal structure of the new indium phosphate

Development of the Chemistry of Indium in Formal Oxidation States Lower than +3

“…Otherwise they are liable to disproportionate or to dimerize with the formation of an In−In-bonded product. Compounds of the type X 2 InInX 2 with tri-coordinated metal atoms survive under normal conditions only in the cases where X is a bulky organic or pseudo-organic substituent, for example, CH(SiMe 3 ) 2 , Trip, or Si t Bu 3 . ,, Preservation of the In−In bond can otherwise be achieved only by expanding the coordination shells of the metal atoms through the inclusion of neutral or anionic donor species, as in In 2 I 4 ·2P n Pr 3 346 and [In 2 Br 6 ] 2- . ,, What approximate to In II 2 pairs are also to be found in the extended structures formed by binary and ternary indium chalcogenides 363-371 and the phosphates In 3 (PO 4 ) 2 and In 2 OPO 4 . , Even more than indium(I) compounds, derivatives of the In II 2 unit are vulnerable to disproportionation, and although examples of addition, metathesis, and oxidation are to be found, a high degree of selectivity is seldom in evidence.…”

“…270,344,345 What approximate to In II 2 pairs are also to be found in the extended structures formed by binary and ternary indium chalcogenides [363][364][365][366][367][368][369][370][371] and the phosphates In 3 (PO 4 ) 2 and In 2 -OPO 4 . 372,373 Even more than indium(I) compounds, derivatives of the In II 2 unit are vulnerable to disproportionation, and although examples of addition, metathesis, and oxidation are to be found, a high degree of selectivity is seldom in evidence.…”

“…A closer approximation to In 2 4+ is probably to be found in the phosphate In 3 (PO 4 ) 2 , the crystal structure of which consists of an anionic network of relatively well isolated PO 4 3tetrahedra balanced by unusually compressed In 2 4+ cationic pairs with r(In-In) ) 2.630(1) Å. 372 The phosphate In 2 OPO 4 also features In 2 4+ cations, but now with r(In-In) ) 2.862(2) Å and in company with In III . 373 Intense Raman scattering at 195 and 163 cm -1 for In 3 (PO 4 ) 2 and In 2 OPO 4 , respectively, has been identified with the ν-(In-In) vibration.…”

“…While these units are often formulated as In 2 4+ , a more accurate description surely calls for a greater degree of delocalization, and the affinity of these systems to molecular diindium(II) compounds is suggested by In−In separations of 2.72−2.82 Å. A closer approximation to In 2 4+ is probably to be found in the phosphate In 3 (PO 4 ) 2 , the crystal structure of which consists of an anionic network of relatively well isolated PO 4 3- tetrahedra balanced by unusually compressed In 2 4+ cationic pairs with r (In−In) = 2.630(1) Å …”