Topological Features of the Alluaudite-Type Framework and Its Derivatives: Synthesis and Crystal Structure of NaMnNi2(H2/3PO4)3

Abstract

A new sodium manganese-nickel phosphate of alluaudite supergroup with the general formula NaMnNi2(H2/3PO4)3 was synthesized by a hydrothermal method. The synthesis was carried out in the temperature range from 540 to 660 K and at the general pressure of 80 atm from the oxides mixture in the molar ratio MnCl2: 2NiCl2: 2Na3PO4: H3BO3: 10H2O. The crystal structure was studied by a single-crystal X-ray diffraction analysis: space group C2/c (No. 15), a = 16.8913(4), b = 5.6406(1), c = 8.3591(3) Å, β = 93.919(3), V = 794.57(4) Å3. The compound belongs to the alluaudite structure type based upon a mixed hetero-polyhedral framework formed by MX6-octahedra and TX4-tetrahedra. The characteristic feature of the title compound is the absence of cations or H2O molecules in channel II, while the negative charge of the framework is balanced by the partial protonation of PO4 tetrahedra. The presence of the transition metals at the A-type sites results in the changes of stoichiometry and the local topological features. Topological analysis of the hetero-polyhedral alluaudite-type frameworks and its derivatives (johillerite-, KCd4(VO4)3-, and keyite-type) and quantitative characterization of their differences was performed by means of natural tilings.

Columbite supergroup of minerals: nomenclature and classification

“…A3.The geometrical characteristics of the squares in the distorted hcp oxygen layers of the Eux -module. Irregularity in the angles of the blue square in comparison with the greenish one, which forms the face of the A O 8 -polyhedron, demonstrates the steric restriction of the direct linkage of two Eux -modules. The influence of the local heteropolyhedral substitutions on the topological features of the parental crystal structures has been shown previously (Aksenov et al , 2021b; 2022b). In the case of ixiolite–euxenite polysomatic series, the euxenite- and samarskite-type structures are characterised by the following tile sequences of the cationic 3 D nets: [3 4 ] 2 [3 2 .4 2 ] 4 [3 4 .4 2 ] 2 [3 8 ] and [3 4 ] 2 [3 2 .4 2 ] 6 [3 4 .4 2 ] 3 [3 8 ], respectively.…”

“…The influence of the local heteropolyhedral substitutions on the topological features of the parental crystal structures has been previously shown (Aksenov et al, 2021b;2022b). In the case of ixiolite-euxenite polysomatic series, the euxenite-and samarskite-type structures are characterized by the following tile sequences of the cationic 3D nets:…”

The role of local heteropolyhedral substitutions in the stoichiometry, topological characteristics and ion-migration paths in the eudialyte-related structures: a quantitative analysis

“…The relationships between heteropolyhedral substitutions and topological features of the derivative framework structures have also been discussed for the alluaudite-supergroup (Aksenov et al, 2021;Hatert, 2019) and the labuntsovitegroup (Chukanov et al, 2002;Aksenov et al, 2018) minerals and related synthetic compounds. However, in the case of eudialyte-type structures such relationships look more complicated because of multiple variants of the derivative structures.…”

“…In this paper, we continue our study (Aksenov et al, 2021(Aksenov et al, , 2020(Aksenov et al, , 2019Kabanova et al, 2020) of the analysis of the role of extra-framework substitutions on the stoichiometry and topological features of heteropolyhedral MT frameworks and provide an analysis of the eudialyte-type framework and its derivatives using the theory of mixed anionic frameworks (Voronkov et al, 1975;Sandomirskiy & Belov, 1984) and possible paths for the ion migrations.…”

Topological analysis of local heteropolyhedral substitutions in the eudialyte-related structures

“…The relationships between heteropolyhedral substitutions and topological features of the derivative framework structures have been also discussed for alluaudite supergroup (Aksenov et al, 2021) minerals and related synthetic compounds. However, in the case of eudialyte-type structures such relationships look more complicated because of multiple variants of their derivative structures.…”