One-dimensional crystal formed inside carbon nanotube

Ars Technica : The discovery of graphene, a sheet of carbon just one atom thick, opened the door to research into two-dimensional materials. And now, the first one-dimensional material—essentially a line of single atoms—has been created. Normally, atoms don’t tend to arrange themselves single file because they need more than two points of contact to be stable. A group of researchers overcame that by condensing vaporized cesium iodide inside a double-walled carbon nanotube. The internal diameter of the tube was between 3.4 Å, the diameter of the atoms, and 8 Å, the amount of space needed for the atoms to arrange themselves in pairs. The resulting structure is more tightly packed than normal CsI crystals and interacts with the carbon atoms in the tube in a way that makes the line not truly one-dimensional. However, the researchers have duplicated the result with several other crystals and intend to study the properties of the new structures.