ChemInform Abstract: Cu₄O₁₂‐Groups of Square Planar CuO₄ Polygones in the Barium Vanadyl Oxocuprate(II) Phosphate Ba(VO)Cu₄(PO₄)₄.

Abstract

Cu 4 O 12 -Groups of Square Planar CuO 4 Polygones in the Barium Vanadyl Oxocuprate(II) Phosphate Ba(VO)Cu 4 (PO 4 ) 4 .-Green single crystals of Ba(VO)Cu 4 (PO 4 ) 4 are obtained by solid-state reaction of BaP 2 O 6 , Cu 3 (PO 4 ) 2 , CuO, V 2 O 5 and V 2 O 3 in 4:4:4:1:1 molar ratio for 3 d at 1030 • C. As revealed from the single-crystal XRD analysis, this compound (tetragonal, P42 1 2 1 , Z = 2) represents a new structure type which is characterized by isolated Cu 4 O 12 and (VO)(PO 4 ) 4 units. The Cu 4 O 12 groups consist of square planar CuO 4 polyhedra which are connected in a hitherto unknown mode. Comparisons with compounds containing planar MO 4 polyhedra are discussed in terms of the crosslinking of these polygones. -(MEYER, S.; MUELLER-BUSCHBAUM, HK.

New arsenate minerals from the Arsenatnaya fumarole, Tolbachik volcano, Kamchatka, Russia. XIX. Axelite, Na14Cu7(AsO4)8F2Cl2

“…In contrast to lavendulan-type minerals and the majority of the structurally related compounds in which, topologically, the same clusters consisting of five tetragonal pyramids and eight T 5+ O 4 tetrahedra ( T = As, P) are connected to form heteropolyhedral layers, in axelite the linkage of the fifth Cu(2)O 4 Cl square pyramid to the neighbouring [Cu 4 O 12 Cl] unit via the common Cl vertex allows the heteropolyhedral chains to be considered as the main building block. Among lavendulan-like compounds, a similar linkage of the fifth tetragonal pyramid to the neighbouring cluster was found in Ba(VO)Cu 4 (PO 4 ) 4 (tetragonal, P 42 1 2, a = 9.5598, c = 7.160 Å: Meyer and Müller-Buschbaum, 1997) (Fig. 4c,d), synthetic phosphates isostructural with this compound A (TiO)Cu 4 (PO 4 ) 4 ( A = Ba, Sr and Pb) (Kimura et al , 2016, 2018), and structurally close K(NbO)Cu 4 (PO 4 ) 4 (tetragonal, P 4 /nmm , a = 9.6865, c = 7.1530 Å: Kimura et al , 2020).…”

“…forming polyhedra] are linked via the tetragonal pyramids which do not participate in the clusters. However, in contrast with Ba(VO)Cu4(PO4)4 (Meyer and Müller-Buschbaum, 1997),…”

“…In axelite topologically close layers [in the case when Na(1)-centred tetragonal pyramids are also considered as the cluster-forming polyhedra] are linked via the tetragonal pyramids which do not participate in the clusters. However, in contrast with Ba(VO)Cu 4 (PO 4 ) 4 (Meyer and Müller-Buschbaum, 1997), phosphates A (TiO)Cu 4 (PO 4 ) 4 ( A = Ba, Sr and Pb) (Kimura et al , 2016, 2018) and K(NbO)Cu 4 (PO 4 ) 4 (Kimura et al , 2020), only one half of these pyramids are present in axelite (Fig. 4): the clusters with Na(1)-centred pyramids are not connected with the additional tetragonal pyramids.…”

“…3.Fragments of the crystal structure of axelite: (a) heteropolyhedral chain built by [Cu(3) 4 O 12 Cl] units, AsO 4 tetrahedra and Cu(2)O 4 Cl square pyramids; an additional Na’ site is shown, its coordination polyhedron is semi-transparent; (b) a fragment consisting of [Na 2 Cu 2 O 12 Cl] clusters, AsO 4 tetrahedra and Na(5)O 8 cubes; (c) dimers built by Na(2) and Na(3) square pyramids.

Fig. 4.Heteropolyhedral Cu–As–O–Cl pseudo-framework in the structure of axelite in two projections (a,b) and Cu–P–V–O pseudo-framework in Ba(VO)Cu 4 (PO 4 ) 4 (c,d, drawn after Meyer and Müller-Buschbaum, 1997). The unit cells are outlined.

Fig.

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“…Heteropolyhedral Cu–As–O–Cl pseudo-framework in the structure of axelite in two projections (a,b) and Cu–P–V–O pseudo-framework in Ba(VO)Cu 4 (PO 4 ) 4 (c,d, drawn after Meyer and Müller-Buschbaum, 1997). The unit cells are outlined.…”