The crystal structure of ginorite, Ca2[B14O20(OH)6]·5H2O, and the analysis of dimensional reduction and structural complexity in the CaO–B2O3–H2O system

Pankova, Yulia A.; Gorelova, Liudmila A.; Krivovichev, Sergey V.; Pekov, Igor V.

doi:10.1127/ejm/2018/0030-2695

Cited by 24 publications

(11 citation statements)

References 52 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For several hydrated crystal structures of Se minerals, the positions of H atoms have not been determined in the original structure reports. In these cases, the H-correction procedure was applied by introducing into structure model of surrogate H atoms [45].…”

Section: Chemical and Structural Complexitymentioning

confidence: 99%

Selenium Minerals: Structural and Chemical Diversity and Complexity

2019

Self Cite

View full text Add to dashboard Cite

Chemical diversity of minerals containing selenium as an essential element has been analyzed in terms of the concept of mineral systems and the information-based structural and chemical complexity parameters. The study employs data for 123 Se mineral species approved by the International Mineralogical Association as of 25 May 2019. All known selenium minerals belong to seven mineral systems with the number of essential components ranging from one to seven. According to their chemical features, the minerals are subdivided into five groups: Native selenium, oxides, selenides, selenites, and selenates. Statistical analysis shows that there are strong and positive correlations between the chemical and structural complexities (measured as amounts of Shannon information per atom and per formula or unit cell) and the number of different chemical elements in a mineral. Analysis of relations between chemical and structural complexities provides strong evidence that there is an overall trend of increasing structural complexity with the increasing chemical complexity. The average structural complexity for Se minerals is equal to 2.4(1) bits per atom and 101(17) bits per unit cell. The chemical and structural complexities of O-free and O-bearing Se minerals are drastically different with the first group being simpler and the second group more complex. The O-free Se minerals (selenides and native Se) are primary minerals; their formation requires reducing conditions and is due to hydrothermal activity. The O-bearing Se minerals (oxides and oxysalts) form in near-surface environment, including oxidation zones of mineral deposits, evaporites and volcanic fumaroles. From the structural viewpoint, the five most complex Se minerals are marthozite, Cu(UO2)3(SeO3)2O2·8H2O (744.5 bits/cell); mandarinoite, Fe2(SeO3)3·6H2O (640.000 bits/cell); carlosruizite, K6Na4Na6Mg10(SeO4)12(IO3)12·12H2O (629.273 bits/cell); prewittite, KPb1.5ZnCu6O2(SeO3)2Cl10 (498.1 bits/cell); and nicksobolevite, Cu7(SeO3)2O2Cl6 (420.168 bits/cell). The mechanisms responsible for the high structural complexity of these minerals are high hydration states (marthozite and mandarinoite), high topological complexity (marthozite, mandarinoite, carlosruizite, nicksobolevite), high chemical complexity (prewittite and carlosruizite), and the presence of relatively large clusters of atoms (carlosruizite and nicksobolevite). In most cases, selenium itself does not play the crucial role in determining structural complexity (there are structural analogues or close species of marthozite, mandarinoite, and carlosruizite that do not contain Se), except for selenite chlorides, where stability of crystal structures is adjusted by the existence of attractive Se–Cl closed-shell interactions impossible for sulfates or phosphates. Most structurally complex Se minerals originate either from relatively low-temperature hydrothermal environments (as marthozite, mandarinoite, and carlosruizite) or from mild (500–700 °C) anhydrous gaseous environments of volcanic fumaroles (prewittite, nicksobolevite).

show abstract

Section: Chemical and Structural Complexitymentioning

confidence: 99%

Selenium Minerals: Structural and Chemical Diversity and Complexity

2019

Self Cite

View full text Add to dashboard Cite

show abstract

“…According to the information-based complexity calculations, the crystal structure of I should be described as complex, with IG = 5.781 bits/atom and IG,total = 625.950 bits/cell (after the procedure of Hcorrection that takes into account the presence of H atoms [31]). It is of interest that teruggite, Ca4Mg[B6As(OH)6O11]2(H2O)14, the only known boroarsenate of natural origin, has almost twice as much information per unit cell, with IG,total = 1201.992 bits/cell.…”

Section: Discussionmentioning

confidence: 99%

“…The construction of the boroarsenate framework agrees well with the bond-valence matching principle formulated by Hawthorne [29]. The linkage between As and B polyhedra involves tetrahedrally coordinated As 5+ and B 3+ , since the [4] As 5+ -O and [4] According to the information-based complexity calculations, the crystal structure of I should be described as complex, with I G = 5.781 bits/atom and I G,total = 625.950 bits/cell (after the procedure of H-correction that takes into account the presence of H atoms [31]). It is of interest that teruggite, Ca 4 Mg[B 6 As(OH) 6 O 11 ] 2 (H 2 O) 14 , the only known boroarsenate of natural origin, has almost twice as much information per unit cell, with I G,total = 1201.992 bits/cell.…”

Section: Discussionmentioning

confidence: 99%

(K,Na)2[AsB6O12]2[B3O3(OH)3], a New Microporous Material, and Its Comparison to Teruggite

Pankova

Krivovichev

2019

Minerals

Self Cite

View full text Add to dashboard Cite

Single crystals of the novel boroarsenate (K,Na) 2 [As 2 B 12 O 24 ][B 3 O 3 (OH) 3 ] (I) were obtained using the borax flux method. The crystal structure of I was found to be triclinic, P-1, a = 8.414(5), b = 10.173(6), c = 15.90(1) Å, α = 79.56(1), β = 78.68(1), γ = 70.91(1), V = 1251(1) Å 3 , Z = 2. The crystal structure of I is based upon the novel [AsB 6 O 12 ] − microporous boroarsenate framework formed by B and As coordination polyhedra. This framework can be subdivided into borate units that are interlinked by AsO 4 tetrahedra. In the case of I, the borate substructure is a chain consisting of triborate rings, 2∆, formed by two (BO 3 ) triangles and one (BO 4 ) tetrahedron connected through shared common oxygen atoms. The chains are extended along [011] and are interlinked by (AsO 4 ) tetrahedra in the [011] direction. As a result, the framework has large channels parallel to [100], having an effective diameter of 4.2 × 5.6 Å 2 . The channels contain occluded electroneutral ring triborate complexes, [B 3 O 3 (OH) 3 ] 0 , formed by three (BO 2 (OH − )) − triangles sharing common O atoms, as well as K + and Na + cations. The triborate [B 3 O 3 (OH) 3 ] 0 units correspond to similar clusters found in the crystal structure of the α-form of metaboric acid, HBO 2 . According to information-based complexity calculations, the crystal structure of I should be described as complex, with I G = 5.781 bits/atom and I G,total = 625.950 bits/cell. Teruggite, Ca 4 Mg[B 6 As(OH) 6 O 11 ] 2 (H 2 O) 14 , the only known boroarsenate of natural origin, has almost twice as much information per unit cell, with I G,total = 1201.992 bits/cell. The observed difference in structural complexity between I and teruggite is the consequence of their chemistry (hydration state) and different formation conditions.

show abstract

“…The high structural complexity of CaUS can be explained by the high topological complexity of the uranyl sulfate chain based upon uranyl hydroxo/oxo hexamers and the high hydration character of the phase. Both features are typical for low-temperature mineral phases that form in the oxidation zones of mineral deposits [37,[44][45][46]. Rod group is an affine subperiodic three-dimensional group type with one-dimensional translation that are classified analogously to the space groups.…”

Section: Discussionmentioning

confidence: 99%

Synchrotron Diffraction Study of the Crystal Structure of Ca(UO2)6(SO4)2O2(OH)6·12H2O, a Natural Phase Related to Uranopilite

et al. 2018

View full text Add to dashboard Cite

The crystal structure of a novel natural uranyl sulfate, Ca(UO2)6(SO4)2O2(OH)6·12H2O (CaUS), has been determined using data collected under ambient conditions at the Swiss–Norwegian beamline BM01 of the European Synchrotron Research Facility (ESRF). The compound is monoclinic, P21/c, a = 11.931(2), b = 14.246(6), c = 20.873(4) Å, β = 102.768(15), V = 3460.1(18) Å3, and R1 = 0.172 for 3805 unique observed reflections. The crystal structure contains six symmetrically independent U6+ atoms forming (UO7) pentagonal bipyramids that share O…O edges to form hexamers oriented parallel to the (010) plane and extended along [1–20]. The hexamers are linked via (SO4) groups to form [(UO2)6(SO4)2O2(OH)6(H2O)4]2− chains running along the c-axis. The adjacent chains are arranged into sheets parallel to (010). The Ca2+ ions are coordinated by seven O atoms, and are located in between the sheets, providing their linkage into a three-dimensional structure. The crystal structure of CaUS is closely related to that of uranopilite, (UO2)6(SO4)O2(OH)6·14H2O, which is also based upon uranyl sulfate chains consisting of hexameric units formed by the polymerization of six (UO7) pentagonal bipyramids. However, in uranopilite, each (SO4) tetrahedron shares its four O atoms with (UO7) bipyramids, whereas in CaUS, each sulfate group is linked to three uranyl ions only, and has one O atom (O16) linked to the Ca2+ cation. The chains are also different in the U:S ratio, which is equal to 6:1 for uranopilite and 3:1 for CaUS. The information-based structural complexity parameters for CaUS were calculated taking into account H atoms show that the crystal structure of this phase should be described as very complex, possessing 6.304 bits/atom and 1991.995 bits/cell. The high structural complexity of CaUS can be explained by the high topological complexity of the uranyl sulfate chain based upon uranyl hydroxo/oxo hexamers and the high hydration character of the phase.

show abstract

The crystal structure of ginorite, Ca2[B14O20(OH)6]·5H2O, and the analysis of dimensional reduction and structural complexity in the CaO–B2O3–H2O system

Cited by 24 publications

References 52 publications

Selenium Minerals: Structural and Chemical Diversity and Complexity

Selenium Minerals: Structural and Chemical Diversity and Complexity

(K,Na)2[AsB6O12]2[B3O3(OH)3], a New Microporous Material, and Its Comparison to Teruggite

Synchrotron Diffraction Study of the Crystal Structure of Ca(UO2)6(SO4)2O2(OH)6·12H2O, a Natural Phase Related to Uranopilite

Contact Info

Product

Resources

About