Extreme pressure turns blue pigment into record-long single-atom copper chains

September 6, 2026 report Extreme pressure turns blue pigment into record-long single-atom copper chains Sanjukta Mondal Author Sadie Harley Scientific Editor Robert Egan Senior Editor As the electronics in our technology keep shrinking, traditional silicon-based chips are approaching their fundamental physical limits. Yet the wires connecting them might be able to shrink beyond conventional dimensions, as scientists have created one of the longest single-atom copper chains to date that could serve as molecular wires. The researchers began with copper phthalocyanine (CuPc), a compound used to make the commonly used blue pigment phthalo blue. Under high pressure—more than 21 gigapascals, roughly 200,000 times normal atmospheric pressure—they converted the CuPc crystals into copper atomic chains stretching for micrometers, each encased in a carbon sheath. The resulting sheathed single-metal-atom chains (sSMACs) resembled a household power cord on an atomic scale, with three distinct layers. The wires exhibited strong anisotropy, meaning electricity flows easily along the wire but has a hard time traveling sideways across it. With more than 4,000 copper atoms strung into a single chain, the structure was two to three orders of magnitude longer than any single-atom chain made before. The previous record stood at just 28 atoms. The findings were published in Science. Atoms in a row The 1D SMACs, considered the thinnest possible metal wires, are gaining attention because of their unusual electronic, magnetic and catalytic properties. Beyond their applications, these structures also give scientists a way to study how matter behaves at the smallest scales. Scientists have successfully created single-atom chains before, but the method has been highly impractical for making longer ones. SMACs are traditionally grown in liquid solutions containing ligands—chemical wrappers that support the metal atoms. The trouble begins when the chains get longer and the wrappers needed to stabilize them become insoluble in the liquid. This brings the synthesis to a halt, resulting in atomic wires that are fewer than 10 atoms long, a problem encountered in almost all previously made SMACs. Ditching the liquids The researchers overcame these limitations by eliminating the liquids entirely and using a high-pressure solid-state reaction. They started with copper phthalocyanine, whose flat, ring-like molecules, each containing a single copper atom, naturally stacked one above another like a column of coins. They placed the pigment crystals inside a tiny, high-pressure device called a diamond anvil cell, which triggered the transformation inside the solid material. The copper atoms were pushed incredibly close together, while the outer carbon rings of adjacent pigment molecules fused to form a tough, diamond-like carbon tube around the copper core. This sheath locked the tightly packed copper atoms into a perfectly straight, stable line. Each nanowire cable has three concentric layers: a core made of a single-atom chain of copper atoms, a conductive ring-like frame made of carbon and nitrogen atoms, and an outer protective carbon sheath (sp3-carbon network) that wraps around the entire wire. Stable and surprising The SMACs were stable in air and survived being bathed in a highly acidic solution for hours under harsh ultrasonic vibrations without breaking. Electricity travels highly selectively through the wires, flowing more than 10 times faster along the wire than sideways in real-world samples. Computer models revealed that if this wire were perfect and defect-free, this electrical flow could be 1,000 times faster along the chain. Magnetic measurements revealed antiferromagnetic interactions between neighboring copper atoms, with their magnetic moments alternating in direction. They also discovered that the copper atoms weren't actually conducting the electricity. Their extremely weak metal-to-metal bonding prevented them from doing so. It was the overlapping carbon and nitrogen atoms in the surrounding protective ring framework that allowed the electrical current to travel down the wire. These properties make a strong case for high-pressure synthesis as a promising route to ultralong atomic copper wires. The catch, however, is that the process demands extreme pressures, a bottleneck that could make scaling up to industrial production difficult. Even so, the researchers are optimistic that this work will open new avenues for exploring the fundamental physics of one-dimensional systems. Written for you by our author Sanjukta Mondal, edited by Sadie Harley, and fact-checked and reviewed by Robert Egan—this article is the result of careful human work. We rely on readers like you to keep independent science journalism alive. If this reporting matters to you, please consider a donation (especially monthly). You'll get an ad-free account as a thank-you. Publication details Jie Zhang et al, Ultralong sheathed single-metal-atom chains synthesized under high pressure, Science (2026). DOI: 10.1126/science.aeg0028 Journal information: Science Key concepts copperAtomic & molecular structureElectrical properties1-dimensional systemsNanostructures© 2026 Science X Network