The Cocrystallization of the Cubic [Ta6Br12(H2O)6][CuBr2X2]·10H2O and Triclinic [Ta6Br12(H2O)6]X2·trans-[Ta6Br12(OH)4(H2O)2]·18H2O (X = Cl, Br, NO3) Phases with the Coexistence of [Ta6Br12]2+ and [Ta6Br12]4+ in the Latter

Abstract

Cubic [Ta 6 Br 12 (H 2 O) 6 ][CuBr 2 X 2 ]·10H 2 O and triclinic [Ta 6 Br 12 (H 2 O) 6 ]X 2 ·trans-[Ta 6 Br 12 (OH) 4 (H 2 O) 2 ]·18H 2 O (X ϭ Cl, Br, NO 3 ) cocrystallize in aqueous solutions of [Ta 6 Br 12 ] 2ϩ in the presence of Cu 2ϩ ions. The crystal structures of [Ta 6 Br 12 (H 2 O) 6 ]Cl 2 ·trans-[Ta 6 Br 12 (OH) 4 (H 2 O) 2 ]·18H 2 O (1) and [Ta 6 Br 12 (H 2 O) 6 ]Br 2 ·trans-[Ta 6 Br 12 (OH) 4 (H 2 O) 2 ]·18H 2 O (3) have been solved in the triclinic space group P 1 (No. 2). Crystal data: 1, a ϭ 9.3264(2) Å , b ϭ 9.8272(2) Å , c ϭ 19.0158(4) Å , Ͱ ϭ 80.931(1)°, β ϭ 81.772(2)°, γ ϭ 80.691(1)°; 3, a ϭ 9.3399(2) Å , b ϭ 9.8796(2) Å , c ϭ 19.0494(4) Å ; Ͱ ϭ 81.037(1)°, β ϭ 81.808(1)°, γ ϭ 80.736 (1)°. 1 and 3 consist of two octahedral differently charged cluster entities, [Ta 6 Br 12 ] 2ϩ in the [Ta 6 Br 12 (H 2 O) 6 ] 2ϩ cation and [Ta 6 Br 12 ] 4ϩ in trans-[Ta 6 Br 12 (OH) 4 (H 2 O) 2 ]. Average bond distances

Synthesis, crystal structure, spectroscopic and thermal properties of [Et4N][Ta6Br12(H2O)6]Br4·4H2O (Et=ethyl)—A new compound with the paramagnetic [Ta6Br12]3+ cluster core

“…are as usual for H 2 O molecules occupying the L a positions[2,3,17,18], although the bond lying in the direction of the four-fold inversion axis (Ta1-O1) is for 0.02Å longer than the perpendicular one (Ta2-O2).TheC-N and C-C bond lengths in [Et 4 N] + are as usually found for the corresponding type of single bonds [1.495 and 1.460Å on average, respectively (taking into account both orientations of the cation)]. The two orientations of the [Et 4 N] + cation can be brought Fig.…”

Hexaaquadodeca-μ-bromo-octahedro-hexatantalum bromide chloride octahydrate

“…This is a non-crystallographic symmetry operation and results in the crystallographic independence of the A and B cluster cations. A similar type of crystal packing has been observed recently in the crystal structures of double salts [Ta 6 Br 12 (H 2 O) 6 ]X 2 Átrans-[Ta 6 Br 12 (OH) 4 (H 2 O) 2 ]Á18H 2 O (X = Cl, compound (II), and X = Br, compound (III)], which contain [Ta 6 Br 12 ] n+ , with n = 2 and 4, simultaneously in the same compound (Vojnovic  et al, 2002). These clusters crystallize in space group P1 with a similar unit cell; the dimensions are: a = 9.3264 (2) A Ê , b = 9.8272 (2) A Ê , c = 19.0158 (4) A Ê , = 80.931 (1) , = 81.772 (2) and = 80.691 (1) for (II), and a = 9.3399 (2) A Ê , b = 9.8796 (2) A Ê , c = 19.0494 (4) A Ê , = 81.037 (1) , = 81.808 (1) and = 80.736 (1) for (III).…”

“…The orientations of clusters A and B in (I), (II) and (III) ( ). Ta6,Ta5,Ta4), (Ta2 iv , Ta1, Ta3 iv ) and (Ta2 iv , Ta1 iv , Ta3 iv ) in (II) and (III) (Vojnovic  et al, 2002), respectively. (b) The angle between the plane de®ned by atoms Ta1, Ta2 and Ta3 and the crystallographic a axis.…”

11 Vanadium, niobium and tantalum

“…The crystal structures determined for the triclinic system (X = Cl, Br) indicate the co-existence of the two differently charged octahedral [Ta 6 Br 12 (H 2 O) 6 ] 2ϩ and [Ta 6 Br 12] 4ϩ . A similar result was not observed in the case of the analogous niobium systems 90.…”