ChemInform Abstract: The Iron Potassium Diarsenate KFeAs<sub>2</sub>O<sub>7</sub> Structural, Electric and Magnetic Behaviors.

Ouerfelli, N.; Guesmi, Abderrahmen; Molinié, P.; Mazza, Daniele; Zid, Mohamed Faouzi; Driss, Ahmed

doi:10.1002/chin.200822025

Cited by 11 publications

(17 citation statements)

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“…The CD method has been mainly used to validate structures, as in the nonstoichiometric mixed oxide YbFeMnO 4 (Nespolo et al, 2000), the oxygen-deficient arsenate Na 7 As 11 O 31 (Guesmi et al, 2006) and the mixed-valent cobalt phosphate Li 4.03 Co 1.97 (P 2 O 7 ) 2 (Kouass et al, 2010); bond-valence analysis has also been used for structural validation and seems to be an important tool to model ionic conduction pathways (e.g. Mazza, 2001;Adams, 2006;Ouerfelli et al, 2008).…”

Section: Figurementioning

confidence: 99%

The novel arsenate Na₄Co_7−xAl_2/3x(AsO₄)₆(x= 1.37): crystal structure, charge-distribution and bond-valence-sum investigations

2010

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The title compound, tetrasodium cobalt aluminium hexaarsenate, Na(4)Co(7-x)Al(2/3x)(AsO(4))(6) (x = 1.37), is isostructural with K(4)Ni(7)(AsO(4))(6); however, in its crystal structure, some of the Co(2+) ions are substituted by Al(3+) in a fully occupied octahedral site (site symmetry 2/m) and a partially occupied tetrahedral site (site symmetry 2). A third octahedral site is fully occupied by Co(2+) ions only. One of the two independent tetrahedral As atoms and two of its attached O atoms reside on a mirror plane, as do two of the three independent Na(+) cations, all of which are present at half-occupancy. The proposed structural model based on a careful investigation of the crystal data is supported by charge-distribution (CHARDI) analysis and bond-valence-sum (BVS) calculations. The correlation between the X-ray refinement and the validation results is discussed.

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Section: Figurementioning

confidence: 99%

The novel arsenate Na₄Co_7−xAl_2/3x(AsO₄)₆(x= 1.37): crystal structure, charge-distribution and bond-valence-sum investigations

2010

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“…the most probable conduction pathways, as well as a good interpretation of the electrical measurements. The procedure and its applications have been reported in many previous works (Mazza, 2001;Ouerfelli et al, 2007Ouerfelli et al, , 2008Marzouki et al, 2013). The BVS pathway simulation is presented first for the pure phosphate phase Na 2 CoP 2 O 7 (Sanz et al, 1999).…”

Section: Tablementioning

confidence: 99%

The influence of P/As substitution in the melilite-like Na₂Co(P_2–xAs_x)O₇(x= 0.40 and 0.93) solid solutions

2017

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To investigate the influence of P/As substitution on structures and electrical properties, e.g. the effect on material densities, two new solid P/As-doped solutions, NaCoPAsO (disodium cobalt diphosphorus arsenic heptaoxide) and NaCoPAsO (disodium cobalt phosphorus arsenic heptaoxide), with melilite-like structures have been synthesized by solid-state reactions. Their unit-cell parameters are in agreement with Vegard's law. The obtained structural models were investigated by the bond valence sum (BVS) and charge distribution (CHARDI) validation tools and, for the latter, the structures are described as being built on anion-centred polyhedra. The frameworks can be described as layered and formed by {[Co(P,As)O]} slabs, with alkali cations sandwiched between the layers and with the interlayer spaces increased due to P/As substitution. The BVS model was extended to a preliminary simulation of the sodium conduction properties in the studied structural type and suggests that the most probable sodium conduction pathways are bidimensional, at the (002) planes.

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“…Metal arsenates often form tetrahedral-octahedral framework structures exhibiting potentially interesting properties, such as ion conductivity, ion exchange and catalytic properties (Masquelier et al, 1990(Masquelier et al, , 1994a(Masquelier et al, ,b, 1995(Masquelier et al, , 1996(Masquelier et al, , 1998Mesa et al, 2000;Ouerfelli et al, 2007aOuerfelli et al, , 2008Pintard-Scré pel et al, 1983;Rousse et al, 2013). During a detailed study of the system M + -M…”

Section: Chemical Contextmentioning

confidence: 99%

KInAs₂O₇, a new diarsenate with the TlInAs₂O₇structure type

Schwendtner

Kolitsch

2017

Acta Cryst E

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Potassium indium diarsenate(V) was grown under mild hydrothermal conditions (T = 493 K, 7 d) at a pH value of about 1. It adopts the TlInAs 2 O 7 structure type (P1, Z = 4) and is closely related to the KAlP 2 O 7 (P2 1 /c) and RbAlAs 2 O 7 (P1) structure types. The framework topology of KInAs 2 O 7 is built of two symmetrically non-equivalent As 2 O 7 groups which share corners with InO 6 octahedra. The K atoms are located in channels extending along [010]. Chemical contextMetal arsenates often form tetrahedral-octahedral framework structures exhibiting potentially interesting properties, such as ion conductivity, ion exchange and catalytic properties (Masquelier et al., 1990(Masquelier et al., , 1994a(Masquelier et al., ,b, 1995(Masquelier et al., , 1996(Masquelier et al., , 1998Mesa et al., 2000;Ouerfelli et al., 2007aOuerfelli et al., , 2008Pintard-Scré pel et al., 1983;Rousse et al., 2013). During a detailed study of the system M + -M 3+-As-O-(H) by hydrothermal syntheses, a large variety of new compounds and structure types were found (Kolitsch, 2004;Schwendtner, 2006;Schwendtner & Kolitsch, 2004a,b, 2005,b,c,d, 2017a. KInAs 2 O 7 is another example of a microporous metal diarsenate compound forming a tetrahedral-octahedral framework structure. M + M 3+ As 2 O 7 compounds crystallize in six known structure types (for a short review, see: Schwendtner & Kolitsch, 2017b), some of these diarsenates being also isotypic to diphosphates or disilicates. For several of the structures, the M + cation is the relevant factor that determines which structure type is adopted, while a wide range of different M 3+ cations are usually accepted. For example, the CaZrSi 2 O 7 structure type (mineral gittinsite; Roelofsen-Ahl & Peterson, 1989) is formed by all Li members (and one Na member), with M 3+ cations ranging from M = Al, Ga, Fe to Sc (Schwendtner & Kolitsch, 2007d;Wang et al., 1994 Table 1).The asymmetric unit contains 22 atoms, all of which lie on general positions. Each InO 6 octahedron shares corners with five different AsO 4 tetrahedra, thus creating a framework structure. Two of these connections are to two AsO 4 tetrahedra of the same As 2 O 7 group (see Fig. 1). The K + cations are situated in small channels extending along [010] (see Fig. 2) and have irregular coordination spheres, with ten (K1) and seven (K2) O atoms within 3.5 Å .The AsO 4 tetrahedra are strongly distorted, with bondlength distortion (Brown & Shannon, 1973) ranging from 0.0020 to 0.0024, while the average As-O distances (1.685, 1.687, 1.689 and 1.690 Å for As1-4, respectively, see Table 1 Comparison of the unit-cell parameters of diarsenates isotypic with KInAs 2 O 7 and closely related structure types. (2015); (7) Kolitsch (2004); (8) Figure 1The principal building unit of KInAs 2 O 7 , shown as displacement ellipsoids at the 70% probability level. The In1O 6 octahedron is considerably more distorted than the In2-centred octahedron. In fact, the In1O 6 octahedron shows the strongest distortion among all of the isotypic In compounds (S...

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ChemInform Abstract: The Iron Potassium Diarsenate KFeAs₂O₇ Structural, Electric and Magnetic Behaviors.

Cited by 11 publications

References 1 publication

The novel arsenate Na₄Co_7−xAl_2/3x(AsO₄)₆(x= 1.37): crystal structure, charge-distribution and bond-valence-sum investigations

The novel arsenate Na₄Co_7−xAl_2/3x(AsO₄)₆(x= 1.37): crystal structure, charge-distribution and bond-valence-sum investigations

The influence of P/As substitution in the melilite-like Na₂Co(P_2–xAs_x)O₇(x= 0.40 and 0.93) solid solutions

KInAs₂O₇, a new diarsenate with the TlInAs₂O₇structure type

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ChemInform Abstract: The Iron Potassium Diarsenate KFeAs2O7 Structural, Electric and Magnetic Behaviors.

Cited by 11 publications

References 1 publication

The novel arsenate Na4Co7−xAl2/3x(AsO4)6(x= 1.37): crystal structure, charge-distribution and bond-valence-sum investigations

The novel arsenate Na4Co7−xAl2/3x(AsO4)6(x= 1.37): crystal structure, charge-distribution and bond-valence-sum investigations

The influence of P/As substitution in the melilite-like Na2Co(P2–xAsx)O7(x= 0.40 and 0.93) solid solutions

KInAs2O7, a new diarsenate with the TlInAs2O7structure type

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ChemInform Abstract: The Iron Potassium Diarsenate KFeAs₂O₇ Structural, Electric and Magnetic Behaviors.

The novel arsenate Na₄Co_7−xAl_2/3x(AsO₄)₆(x= 1.37): crystal structure, charge-distribution and bond-valence-sum investigations

The novel arsenate Na₄Co_7−xAl_2/3x(AsO₄)₆(x= 1.37): crystal structure, charge-distribution and bond-valence-sum investigations

The influence of P/As substitution in the melilite-like Na₂Co(P_2–xAs_x)O₇(x= 0.40 and 0.93) solid solutions

KInAs₂O₇, a new diarsenate with the TlInAs₂O₇structure type