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A First‐Principles Study on the Electronic, Vibrational, and Thermodynamic Properties of Jadeite and its Tentative Low‐Density Polymorph
Author(s) -
Stoffel Ralf Peter,
Philipps Katharina,
Conradt Reinhard,
Dronskowski Richard
Publication year - 2016
Publication title -
zeitschrift für anorganische und allgemeine chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.354
H-Index - 66
eISSN - 1521-3749
pISSN - 0044-2313
DOI - 10.1002/zaac.201600071
Subject(s) - bulk modulus , molar volume , phase (matter) , octahedron , tetrahedron , density functional theory , thermodynamics , materials science , phonon , chemistry , crystallography , crystal structure , computational chemistry , condensed matter physics , physics , organic chemistry
The high‐pressure clinopyroxene mineral jadeite (chemical composition NaAlSi 2 O 6 ) was studied by density‐functional theory with respect to its electronic, vibrational, and thermodynamic properties, correctly reproducing the available experimental data. At a larger‐than‐normal volume, however, a low‐density alumosilicate phase with tetrahedral instead of octahedral Al–O coordination was identified. This low‐density phase was investigated theoretically, too, and the results were compared to jadeite and experimentally observed properties of what has been dubbed jadeite glass. It turned out that the theoretically obtained properties of this hypothetical polymorph, such as the bulk modulus, the molar volume and the vibrational frequencies, agree well with the corresponding properties of the glass phase. Hence, from an inverse structure‐property relationship we propose to model jadeite glass with the aforementioned low‐density alumosilicate phase and tetrahedral Al–O motifs, as suggested from first principles and corroborated from experiment. The possibilities as well as the limitations of electronic, phonon and thermodynamic properties calculations applied to such a polymorph are also discussed.