Paul J. Steinhardt, Harvard University, Cambridge, MA, USA, and colleagues have discovered in the 4.5 billion year old Khatyrka meteorite a previously unknown natural quasicrystal. The quasicrystal has the composition Al71Ni24Fe5 and is the first known natural quasicrystal with decagonal symmetry: the structure resembles a ten square disks stack and thus has a structure that previously was considered as impossible for a crystal.
Icosahedrite, Al63Cu24Fe13, the first natural quasicrystal to be identified, was found in the same meteorite. The new quasicrystal was found associated with steinhardtite (Al38Ni32Fe30), Fe-poor steinhardtite (Al50Ni40Fe10), Al-bearing trevorite (NiFe2O4) and Al-bearing taenite (FeNi). Laboratory studies of Al71Ni24Fe5 have shown that it is stable over a narrow range of temperatures, 1120–1200 K at standard pressure.
The researchers want to find out whether the formation of quasicrystals is rare or relatively common, how it happens, and whether it could also occur in other solar systems. This could answer basic questions about the materials that we find in our universe.
- Natural quasicrystal with decagonal symmetry,
Luca Bindi, Nan Yao, Chaney Lin, Lincoln S. Hollister, Christopher L. Andronicos, Vadim V. Distler, Michael P. Eddy, Alexander Kostin, Valery Kryachko, Glenn J. MacPherson, William M. Steinhardt, Marina Yudovskaya, Paul J. Steinhardt,
Sci. Rep. 2015, 5, 9111.
Also of interest:
- Quasicrysals Originate from Meteorite,
ChemistryViews.org 19 August 2012.
So far only natural quasicrystal was found in a rock sample composed in eastern Russia originating from a meteorite that fell to Eart
- Dan Shechtman: Succeeding in Science,
Vera Koester and Christian Remenyi,
ChemViews Mag. 2013.
Nobel Laureate Dan Shechtman talks about the reason why quasicrystals weren’t discovered earlier and his unerring belief in his experiments