Journal: Nature Materials
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Close encounters of the fourth kind
Scientists have discovered a new crystallographic phase in ceramic metal oxides.
Solids are classified into three categories — crystalline, quasicrystalline and amorphous — depending on their atomic arrangements.
Crystalline materials exhibit both translational symmetry, in which arrangements of atoms repeat themselves along three axes, and rotational symmetry, where the structure looks identical after being rotated around an axis. Quasicrystalline materials, however, exhibit only rotational symmetry, while amorphous materials have neither translational nor rotational symmetry.
Now, a team of scientists, all from the Advanced Institute for Materials Research in Japan, has found two ceramic materials — magnesium oxide and neodymium oxide — with one-dimensional ordered crystal structures that differ to the atomic arrangements found in known solid structures.
The work has revealed a fourth way in which atoms can arrange themselves in solids.
- Nature Materials 18, 19–23 (2019). doi: 10.1038/s41563-018-0240-0