A Mero-Plesiotype Series of Vanadates, Arsenates, and Phosphates with Blocks Based on Densely Packed Octahedral Layers as Repeating Modules

Olga Yakubovich,Galina Kiriukhina

doi:10.3390/min11030273

Olga Yakubovich, Galina Kiriukhina

Open Access

https://doi.org/10.3390/min11030273

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Abstract

The family of layered vanadates, arsenates, and phosphates is discussed in terms of a modular concept. The group includes minerals vésignéite and bayldonite, and a number of synthetic analogous and modifications which are not isotypic, but their crystal structures comprise similar blocks (modules) consisting of a central octahedral layer filled by atoms of d elements (Mn, Ni, Cu, or Co) and adjacent [VO4], [AsO4], or [PO4] tetrahedra. The octahedral layers are based on the close-packing of oxygen atoms. Within these layers having the same anionic substructure, the number and distribution of octahedral voids are different. In the crystal structures of compounds participating in the polysomatic series, these blocks alternate with various other structural fragments. These circumstances define the row of structurally-related vanadates, arsenates, and phosphates as a mero-plesiotype series. Most of the series members exhibit magnetic properties, representing two-dimensional antiferromagnets or frustrated magnets.

Highlights

IntroductionThe modular approach for interpreting the crystal structures of minerals is well known
The modular approach for interpreting the crystal structures of minerals is well known.Its intensive use in modern crystal chemistry has become possible after the pioneer works of Thomson [1,2,3] and Veblen [4]
The crystal structure can be interpreted as a derivative of diverse modules; it is meant as a polysome

Summary

Introduction

The modular approach for interpreting the crystal structures of minerals is well known. To expand the field of structurally-related compounds within the polysomatic series, Makovicky [5] proposed to adopt a possibility of variations both in the structure and in the chemical composition of modules still keeping their topological similarity. These advanced sequences of compounds were called mero-plesiotype series. A noticed similarity of their crystal architecture completed with research on structurally-related synthetic phases and minerals allowed us to establish a new polysomatic series of vanadates, arsenates, and phosphates with densely packed octahedral layers decorated by tetrahedra, as repeating fragments

The Main Module Topology

Conclusions