Structure cristalline de l'oxotrioxalatoniobate d'ammonium à une molécule d'eau, (NH4)3NbO(C2O4)3.H2O

Abstract

The crystal structure of ammonium oxotrioxalatoniobate (NH4)3NbO(C204)3.H20 has been determined by X-ray diffraction. Crystals are triclinic with a=9.20+0.01, b=13-57+0.02, c=7.68+0.01 A; e=93-0+0-2, fl= 123"1 +0.2, 7 = 107"9+0"2°; Z=2; space group PT. The coordination polyhedron of niobium is a pentagonal bipyramid. Steric interactions between the ligands produce a displacement of the niobium out of the equatorial plane. The Nb-O (terminal) distance is 1.71 A and the Nb-O (oxalate) mean distance is 2.13 A..

The crystal structure of caesium oxobisoxalatobisaquoniobate(V) dihydrate, Cs[NbO(C2O4)2(H2O)2].H2O

“…These bond lengths are in agreement with the values found in some other coordinated oxalato complexes, e. g. in (NH4)3[NbO(C204)3]. H20, (Mathern & Weiss, 1971) and K2[MoO(O2)2C204], (Stomberg, 1970). The C(1)-C(2) bond of length 1.533(5)/~ can be compared with that in ethane (1.536 ,~).…”

“…The niobium-oxygen distances from the oxalato group of 2.104(3) A and 2.124(2) A are not significantly different from the values reported earlier, e. g. 2.114 to 2.157 A in (NH4)3[NbO(C204)z].H20 (Mathern & Weiss, 1971) and 2.07 .A to 2.12A in NH4[NbO(C204)2 (H20)2].3H20 (Galegi6, Matkovi6,Herceg & ~ljuki6, 1971). Although the Nb-OW(1) distance of 2.169 A is somewhat longer than the corresponding niobiumoxygen distances from the oxalato group, these differences in the niobium-oxygen distances have a small influence on the regularity of the pentagonal plane.…”

“…Only one crystal structure determination of a niobium trisoxalato complex has been reported (Mathern & Weiss, 1971). The present structure determination is part of a structural investigation of niobium bisoxalato complexes (Galegid, Matkovi6, Herceg & Sljukid, 1971) prepared recently (Brni6evi6 & Dordevi6, 1971).…”

Spectroscopic and Structural Characterizations of Novel Water‐Soluble Peroxo[polyaminocarboxylato bis(N‐oxido)]niobate(V) Complexes

“…Because peroxoniobium compounds are soluble in water, they are adequate candidates for that purpose. Several such complexes have already been described in the literature; they correspond either to homoleptic tetraperoxoniobates of general formula (A I ) 3 [9,11] and K[Nb(O 2 ) 2 (L) 2 ]·3H 2 O (L ϭ 8-hydroxyquinolinate). [12] As far as the peroxo(polyaminocarboxylato) compounds are concerned, only a few studies have been reported and they are essentially restricted to the edta(peroxo) compound [a] and its solution chemistry.…”

Structures cristallines et moléculaires des composés d'addition du pentachlorure d'antimoine et des chlorures de benzoyle et de m-toluyle

“…Les donndes cristallographiques sont indiqu6es dans le Tableau 1. (Mathern & Weiss, 1971) La position des atomes d'antimoine a 6t6 d6termin4e par l'identification des pseudoatomes Sb-Sb dans la fonction, de Patterson tridimensionnelle. En utilisant la m6thode de l'atome lourd, le calcul de la densit6 41ectronique par des s6ries de Fourier tridimensionnelle a r6v616 la position de tous les atomes de chlore, d'oxyg6ne et de carbone.…”