Redetermination and new description of the crystal structure of vanthoffite, Na6Mg(SO4)4
Publikation: Bidrag til tidsskrift › Review › Forskning › fagfællebedømt
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Redetermination and new description of the crystal structure of vanthoffite, Na6Mg(SO4)4. / Balić-Žunić, Tonči; Pamato, Martha G.; Nestola, Fabrizio.
I: Acta Crystallographica Section E: Crystallographic Communications, Bind 76, Nr. 6, 2020, s. 785-789.Publikation: Bidrag til tidsskrift › Review › Forskning › fagfællebedømt
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TY - JOUR
T1 - Redetermination and new description of the crystal structure of vanthoffite, Na6Mg(SO4)4
AU - Balić-Žunić, Tonči
AU - Pamato, Martha G.
AU - Nestola, Fabrizio
PY - 2020
Y1 - 2020
N2 - The crystal structure of vanthoffite {hexasodium magnesium tetrakis-[sulfate(VI)]}, Na6Mg(SO4)4, was solved in the year 1964 on a synthetic sample [Fischer & Hellner (1964). Acta Cryst. 17, 1613]. Here we report a redetermination of its crystal structure on a mineral sample with improved precision. It was refined in the space group P21/c from a crystal originating from Surtsey, Iceland. The unique Mg (site symmetry 1) and the two S atoms are in usual, only slightly distorted octahedral and tetrahedral coordinations, respectively. The three independent Na atoms are in a distorted octahedral coordination (1×) and distorted 7-coordinations intermediate between a ‘split octahedron’ and a pentagonal bipyramid (2×). [MgO6] coordination polyhedra interchange with one half of the sulfate tetrahedra in <011> chains forming a (100) meshed layer, with dimers formed by edge-sharing [NaO7] polyhedra filling the interchain spaces. The other [NaO7] polyhedra are organized in a parallel layer formed by [010] and [001] chains united through edge sharing and bonds to the remaining half of sulfate groups and to [NaO6] octahedra. The two types of layers interconnect through tight bonding, which explains the lack of morphological characteristics typical of layered structures.
AB - The crystal structure of vanthoffite {hexasodium magnesium tetrakis-[sulfate(VI)]}, Na6Mg(SO4)4, was solved in the year 1964 on a synthetic sample [Fischer & Hellner (1964). Acta Cryst. 17, 1613]. Here we report a redetermination of its crystal structure on a mineral sample with improved precision. It was refined in the space group P21/c from a crystal originating from Surtsey, Iceland. The unique Mg (site symmetry 1) and the two S atoms are in usual, only slightly distorted octahedral and tetrahedral coordinations, respectively. The three independent Na atoms are in a distorted octahedral coordination (1×) and distorted 7-coordinations intermediate between a ‘split octahedron’ and a pentagonal bipyramid (2×). [MgO6] coordination polyhedra interchange with one half of the sulfate tetrahedra in <011> chains forming a (100) meshed layer, with dimers formed by edge-sharing [NaO7] polyhedra filling the interchain spaces. The other [NaO7] polyhedra are organized in a parallel layer formed by [010] and [001] chains united through edge sharing and bonds to the remaining half of sulfate groups and to [NaO6] octahedra. The two types of layers interconnect through tight bonding, which explains the lack of morphological characteristics typical of layered structures.
KW - Atomic coordinations
KW - Crystal structure
KW - Na-Mg sulfate
KW - Redetermination
KW - Vanthoffite
U2 - 10.1107/S2056989020005873
DO - 10.1107/S2056989020005873
M3 - Review
C2 - 32523739
AN - SCOPUS:85086088507
VL - 76
SP - 785
EP - 789
JO - Acta Crystallographica Section E: Crystallographic Communications
JF - Acta Crystallographica Section E: Crystallographic Communications
SN - 1600-5368
IS - 6
ER -
ID: 243377277