TY - JOUR
T1 - Previously unknown quasicrystal periodic approximant found in space
AU - Bindi, Luca
AU - Pham, Joyce
AU - Steinhardt, Paul J.
N1 - Funding Information:
We wish to thank the 2011 expeditionary team composed by: Christopher L. Andronicos, Vadim V. Distler, Michael P. Eddy, Alexander Kostin, Valery Kryachko, Glenn MacPherson, William Steinhardt and Marina Yudovskaya. Special thanks are also due to Lincoln Hollister and Nan Yao for their invaluable help in the different stages of this project. This work was supported in part by “Progetto di Ateneo 2015” of the University of Florence, Italy (L.B.), the National Science Foundation-MRSEC program through New York University (DMR-0820341; P.J.S.). We are also grateful to the anonymous donor who supported the 2011 expedition to Chukotka through a grant to Princeton University (P.J.S., Principal Investigator).
Publisher Copyright:
© 2018, The Author(s).
PY - 2018/12/1
Y1 - 2018/12/1
N2 - We report the discovery of Al34Ni9Fe2, the first natural known periodic crystalline approximant to decagonite (Al71Ni24Fe5), a natural quasicrystal composed of a periodic stack of planes with quasiperiodic atomic order and ten-fold symmetry. The new mineral has been approved by the International Mineralogical Association (IMA 2018-038) and officially named proxidecagonite, which derives from its identity to periodic approximant of decagonite. Both decagonite and proxidecagonite were found in fragments from the Khatyrka meteorite. Proxidecagonite is the first natural quasicrystal approximant to be found in the Al-Ni-Fe system. Within this system, the decagonal quasicrystal phase has been reported to transform at ~940 °C to Al13(Fe,Ni)4, Al3(Fe,Ni)2 and the liquid phase, and between 800 and 850 °C to Al13(Fe,Ni)4, Al3(Fe,Ni) and Al3(Fe,Ni)2. The fact that proxidecagonite has not been observed in the laboratory before and formed in a meteorite exposed to high pressures and temperatures during impact-induced shocks suggests that it might be a thermodynamically stable compound at high pressure. The most prominent structural motifs are pseudo-pentagonal symmetry subunits, such as pentagonal bipyramids, that share edges and corners with trigonal bipyramids and which maximize shortest Ni–Al over Ni–Ni contacts.
AB - We report the discovery of Al34Ni9Fe2, the first natural known periodic crystalline approximant to decagonite (Al71Ni24Fe5), a natural quasicrystal composed of a periodic stack of planes with quasiperiodic atomic order and ten-fold symmetry. The new mineral has been approved by the International Mineralogical Association (IMA 2018-038) and officially named proxidecagonite, which derives from its identity to periodic approximant of decagonite. Both decagonite and proxidecagonite were found in fragments from the Khatyrka meteorite. Proxidecagonite is the first natural quasicrystal approximant to be found in the Al-Ni-Fe system. Within this system, the decagonal quasicrystal phase has been reported to transform at ~940 °C to Al13(Fe,Ni)4, Al3(Fe,Ni)2 and the liquid phase, and between 800 and 850 °C to Al13(Fe,Ni)4, Al3(Fe,Ni) and Al3(Fe,Ni)2. The fact that proxidecagonite has not been observed in the laboratory before and formed in a meteorite exposed to high pressures and temperatures during impact-induced shocks suggests that it might be a thermodynamically stable compound at high pressure. The most prominent structural motifs are pseudo-pentagonal symmetry subunits, such as pentagonal bipyramids, that share edges and corners with trigonal bipyramids and which maximize shortest Ni–Al over Ni–Ni contacts.
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U2 - 10.1038/s41598-018-34375-x
DO - 10.1038/s41598-018-34375-x
M3 - Article
C2 - 30389957
AN - SCOPUS:85056049123
SN - 2045-2322
VL - 8
JO - Scientific reports
JF - Scientific reports
IS - 1
M1 - 16271
ER -