The ratio worth doing by hand is 4,000 over 28. That comes to roughly 143 times, or just past two orders of magnitude [14], which places the "two to three orders of magnitude" in the phys.org account at the low end of its own range [3]. It is still a large jump in a field where nearly every earlier chain stalled below 10 atoms, because the ligands needed to stabilise a longer chain stopped dissolving in the solution growing it [9]. The result was published in Science [4].
The design matters more than the record. Copper phthalocyanine molecules are flat rings with one copper atom apiece, and in the crystal they stack like a column of coins [10]. Compressing that crystal drives the coppers together while the outer rings of neighbouring molecules fuse into a diamond-like carbon tube, which pins the copper into a straight line [11]. Container and contents come out of the same molecule in the same step, and that is why the product survives handling: hours in a strongly acidic bath under harsh ultrasonic vibration, and stability in air [7]. Single-atom chains tend to be fragile, but this one comes wrapped in its own armour, which is why it holds up under that kind of treatment.
Then the measurement that complicates the interconnect story. The copper atoms do not carry the current. Metal-to-metal bonding along the chain is too weak, and conduction instead runs through the overlapping carbon and nitrogen atoms of the ring framework wrapped around the core [5]. Magnetically the copper still behaves like a chain, with antiferromagnetic coupling between neighbours and moments alternating in direction [8]. As a wire, though, the metal core works as scaffolding for the carbon-nitrogen conductor wrapped around it.
On the electrical side the reported number is a ratio: current flows more than 10 times faster along real samples than across them, and a model of a defect-free chain gives 1,000 times [6]. Anisotropy of that kind tells you the structure is genuinely one-dimensional in its transport. The thing it does not tell you is resistivity, how much current the wire tolerates before it fails, or what happens at the contacts, none of which appear in this account [16]. Those are the quantities a wiring decision turns on, and the gap between 10x measured and 1,000x modelled is a defect-density problem, not a rounding error.
So the framing of shrinking chip interconnects sits awkwardly on this work. Silicon scaling limits are the motivation phys.org offers, and one-dimensional single-metal-atom chains are the thinnest metal wires anyone can imagine [13][15], but the demonstration here is a synthesis result: solid-state, solvent-free, and dependent on more than 21 gigapascals, about 200,000 atmospheres, inside a diamond anvil cell [1]. Phys.org names that pressure requirement as the bottleneck for industrial production [12]. Chain length is no longer capped by solubility; that much is established. Whether anything on this route can be wired to anything else is not.
