Hydrogen bonding and structural complexity in the Cu5(PO4)2(OH)4 polymorphs (pseudomalachite, ludjibaite, reichenbachite): combined experimental and theoretical study

Krivovichev, Sergey V.; Zolotarev, Andrey A.; Попова, В. И.

doi:10.1007/s11224-016-0820-z

Cited by 16 publications

(6 citation statements)

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“…In order to analyze the phase evolution within the family of calcium oxalate compounds, we studied their complexity in terms of the information-based approach developed in refs − and implemented in refs − . The structural complexity is quantitatively estimated as the Shannon information content per atom ( I G ) and per unit cell ( I G,total ) using the following equations: where k is the number of different crystallographic orbits (independent crystallographic Wyckoff sites) in the structure, and p i is the random choice probability for an atom from the i th crystallographic orbit, that is where m i is a multiplicity of a crystallographic orbit (i.e., the number of atoms of a specific Wyckoff site in the reduced unit cell), and v is the total number of atoms in the reduced unit cell.…”

Section: Resultsmentioning

confidence: 99%

Hydrated Calcium Oxalates: Crystal Structures, Thermal Stability, and Phase Evolution

Izatulina

Gurzhiy

Krzhizhanovskaya

et al. 2018

Crystal Growth & Design

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Thermal stability, structural evolution pathways, and phase transition mechanisms of the calcium oxalates whewellite (CaC2O4·H2O), weddellite (CaC2O4·(2+x)H2O), and caoxite (CaC2O4·3H2O) have been analyzed using single crystal and powder X-ray diffraction (XRD). During single crystal XRD heating experiments, α-CaC2O4 and the novel calcium oxalate monohydrate have been obtained and structurally characterized for the first time. The highest thermal expansion of these compounds is observed along the direction of the hydrogen bonds, whereas the lowest expansion and even contraction of the structures occur due to the displacement of neighbor layered complexes toward each other and to an orthogonalization of the monoclinic angles. Within the calcium oxalate family, whewellite should be regarded as the most stable crystalline phase at ambient conditions. Weddellite and caoxite transform to whewellite during dehydration-driven phase transition promoted by time and/or heating.

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Section: Resultsmentioning

confidence: 99%

Hydrated Calcium Oxalates: Crystal Structures, Thermal Stability, and Phase Evolution

Izatulina

Gurzhiy

Krzhizhanovskaya

et al. 2018

Crystal Growth & Design

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“…The structural complexity parameters, which are estimated as a Shannon information content per atom ( I G ) and per unit cell ( I G,total ), were calculated to analyze structural variations occurring due to the Se-for-S substitution. According to this approach recently reported in refs − and applied in refs , , , and − , complexity of the crystal structure can be determined by the amount of Shannon information it contains and measured in bits per atom and per unit cell. The amount of Shannon information reflects multiplicity and the number of different crystallographic sites in a reduced unit cell of a structure.…”

Section: Resultsmentioning

confidence: 99%

Chemically Induced Polytypic Phase Transitions in the Mg[(UO₂)(TO₄)₂(H₂O)](H₂O)₄ (T = S, Se) System

et al. 2019

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Chemically induced polytypic phase transitions have been observed during experimental investigations of crystallization in the mixed uranyl sulfate-selenate Mg[(UO2)(TO4)2(H2O)](H2O)4 (T = S, Se) system. Three different structure types form in the system, depending upon the Se:S ratio in the initial aqueous solution. The phases with the Se/(Se + S) ratios (in mol %) in the ranges 0–9, 16–47, and 58–100 crystallize in the space groups P21, Pmn21, and P21/c, respectively. The structures of the phases are based upon the same type of uranyl-based sulfate/selenate chains that, through hydrogen bonds, are linked into pseudolayers of the same topological type. The layers are linked into three-dimensional structures via interlayer Mg-centered octahedra. The three structure types contain the same layers but with different stacking sequences that can be conveniently described as belonging to the 1M, 2O, and 2M polytypic modifications. The Se-for-S substitution demonstrates a strong selectivity with preferential incorporation of Se into less tightly bonded T1 site. The larger ionic radius of Se6+ relative to S6+ induces rotation of (T1O4) tetrahedra in the adjacent layers and reconstruction of the structure types. From the information-theoretic viewpoint, the intermediate Pmn21 structure type is more complex than the monoclinic end-member structure types.

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“…In order to evaluate the influence of various crystal-chemical factors (such as dimensionality of the uranium-bearing units and their hydration state) on the structure and symmetry of uranyl sulfate complexes and on the structural architecture of minerals in general, the structural and topological complexity was studied in terms of the information-based approach developed by Krivovichev (2012Krivovichev ( , 2013Krivovichev ( , 2014 and recently used by Cempírek et al (2016), Gurzhiy et al (2016Gurzhiy et al ( , 2017Gurzhiy et al ( , 2018a, Krivovichev et al (2016Krivovichev et al ( , 2017, Majzlan et al (2018) and Plá šil (2018a,b). The structural complexity is quantitatively estimated as a Shannon information content per atom (I G ) and per unit cell (I G,total ).…”

Section: Complexity Calculationsmentioning

confidence: 99%

Structural complexity of natural uranyl sulfates

Gurzhiy

Plášil

2019

Acta Crystallogr Sect B

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Uranyl sulfates, including those occurring in Nature (∼40 known members), possess particularly interesting structures. They exhibit a great dimensional and topological diversity of structures: from those based upon clusters of polyhedra to layered structures. There is also a great variability in the type of linkages between U and S polyhedra. From the point of view of complexity of those structures (measured as the amount of Shannon information per unit cell), most of the natural uranyl sulfates are intermediate (300–500 bits per cell) to complex (500–1000 bits per cell) with some exceptions, which can be considered as very complex structures (>1000 bits per cell). These exceptions are minerals alwilkinsite‐(Y) (1685.95 bits per cell), sejkoraite‐(Y) (1859.72 bits per cell), and natrozippeite (2528.63 bits per cell). The complexity of these structures is due to an extensive hydrogen bonding network which is crucial for the stability of these mineral structures. The hydrogen bonds help to propagate the charge from the highly charged interlayer cations (such as Y3+) or to link a high number of interlayer sites (i.e. five independent Na sites in the monoclinic natrozippeite) occupied by monovalent cations (Na+). The concept of informational ladder diagrams was applied to the structures of uranyl sulfates in order to quantify the particular contributions to the overall informational complexity and identifying the most contributing sources (topology, real symmetry, interlayer bonding).

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Hydrogen bonding and structural complexity in the Cu5(PO4)2(OH)4 polymorphs (pseudomalachite, ludjibaite, reichenbachite): combined experimental and theoretical study

Cited by 16 publications

References 41 publications

Hydrated Calcium Oxalates: Crystal Structures, Thermal Stability, and Phase Evolution

Hydrated Calcium Oxalates: Crystal Structures, Thermal Stability, and Phase Evolution

Chemically Induced Polytypic Phase Transitions in the Mg[(UO₂)(TO₄)₂(H₂O)](H₂O)₄ (T = S, Se) System

Structural complexity of natural uranyl sulfates

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Hydrogen bonding and structural complexity in the Cu5(PO4)2(OH)4 polymorphs (pseudomalachite, ludjibaite, reichenbachite): combined experimental and theoretical study

Cited by 16 publications

References 41 publications

Hydrated Calcium Oxalates: Crystal Structures, Thermal Stability, and Phase Evolution

Hydrated Calcium Oxalates: Crystal Structures, Thermal Stability, and Phase Evolution

Chemically Induced Polytypic Phase Transitions in the Mg[(UO2)(TO4)2(H2O)](H2O)4 (T = S, Se) System

Structural complexity of natural uranyl sulfates

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Chemically Induced Polytypic Phase Transitions in the Mg[(UO₂)(TO₄)₂(H₂O)](H₂O)₄ (T = S, Se) System