A peer-reviewed Science paper, microscopy data, multireference calculations and independent reporting support the first half-Möbius C13Cl2 molecule; the social-media wording overstates the quantum computer as having experimentally “validated entanglement.”
IBM creates first half-twisted ring molecule
Scientists construct a tiny carbon circle with a novel electron loop at minus 268 degrees Celsius
In a nutshell
Researchers have synthesized C13Cl2, an engineered 13-carbon ring whose electron system completes a 90-degree twist per cycle, establishing chemistry's first half-Möbius molecule. Verified through atomic microscopy at cryogenic temperatures and checked using 72-qubit quantum simulations, the molecule can be reversibly switched between distinct electronic shapes, though it remains confined to ultra-cold vacuum surfaces.
Highlights
- Voltage pulses between 4.5 and 5 volts removed eight chlorines to build C13Cl2 one molecule at a time.
- The electron basis twists 90 degrees around the loop, needing four full turns to reset to its original sign.
- The physical carbon ring tilts only 24 degrees, showing the twist belongs primarily to the electron orbitals.
- The non-planar singlet state sits 0.44 electron-volts below the flat triplet form on insulating salt.
- Quantum calculations deployed 72 qubits to model 32 correlated electrons without altering classical predictions.
Electronic and structural parameters of C13Cl2
| Parameter | Value |
|---|---|
| Physical ring distortion (degrees) | 24 |
| Chlorine bond tilt angle (degrees) | 12 |
| Electronic basis twist per circuit (degrees) | 90 |
| Singlet ground state energy advantage (eV) | 0.44 |
| Switching voltage threshold (mV) | 210 |
- Structural tilt angles, orbital twists, energy differences and electrical switching thresholds measured and calculated for C13Cl2.
- The figures confirm that the half-Möbius property is an electronic orbital phenomenon rather than an extreme mechanical deformation of the carbon ring.
From the Editor’s Diary
Extreme molecular geometries can stabilize fragile electron configurations, but real-world utility requires moving exotic topologies from single-atom vacuum stages into room-temperature bulk chemistry.
Who's involved
IBM Research Europe–Zurich
Swiss laboratory that assembled, imaged and switched the individual molecules while leading the quantum computing calculations
goal → show atom-by-atom control of a novel electronic layout and test quantum processors on real chemical data
Igor Rončević and the University of Manchester
computational chemistry team leading the theoretical interpretation of the molecular structure
goal → explain why the molecule adopts its twisted form and define the physics of its electron loop
Leo Gross
lead microscope scientist at IBM Research Europe–Zurich who co-designed the experiment
goal → assemble, photograph and flip the unusual molecule using atomic probes
Oxford University chemistry team
synthetic chemists Harry Anderson and Yueze Gao who produced the starting compound
goal → supply the chemical precursor and connect the finding to previous carbon-ring experiments
IBM Quantum, ETH Zurich and EPFL
quantum computing and theory specialists including Stefano Barison, Samuele Piccinelli, Alberto Baiardi and Ivano Tavernelli
goal → evaluate larger electron-interaction models on quantum processors using the new SqDRIFT algorithm
University of Regensburg
German academic partner represented by Jascha Repp on scanning microscopy and theory
goal → verify the molecular geometry and evaluate its electrically switched states
In short
TL;DR: Scientists have created C13Cl2, the first molecule whose electrons form a half-twisted circuit, using microscope pulses at ultra-cold temperatures. The work proves an exotic electronic pattern can exist in real matter, though practical devices remain a distant prospect.
Q: How does the half-twisted molecule work and what was proved?
- IBM and university researchers built C13Cl2 by stripping eight chlorine atoms from a precursor on salt at 5 K.
How it unfolded
Oxford and IBM spot an accidental clue in carbon-ring tests
The quest began as an attempt by Oxford University and IBM scientists to make a pure 13-carbon ring by peeling chlorine atoms off a larger molecule on a cold surface. When Science published that original synthesis, researchers noticed an intermediate fragment carrying two chlorine atoms that behaved strangely, displaying distinct mirror-image forms and switching under electric voltage. The team chose not to announce the observation immediately, spending the next year testing whether the mystery compound represented an entirely new class of molecular twist.
Researchers reveal first evidence of a quarter-twist electron loop
The team went public fourteen months later, posting experimental results asserting that the intermediate molecule, C13Cl2, possessed an unprecedented 90-degree twist in its electron cloud. Microscope images showed that the ring adopted two mirror-image chiral forms and could flip between them under an electric tip. The initial paper relied on conventional chemical modeling without mentioning quantum processors, but a month later IBM researchers posted a separate computing algorithm tailored to run complex molecular electron problems on quantum hardware.
Quantum hardware joins the investigation to verify electron mixing
The molecular study grew substantially in late 2025 when quantum computing specialists joined the author list. The team deployed a 72-qubit quantum processor to analyze 32 interacting electrons within the ring, examining all 24 carbon electrons alongside eight chlorine electrons. Rather than contradicting earlier classical calculations, the larger quantum run closely matched a 12-electron conventional model, assuring the researchers that basic structural strain caused the in-plane and out-of-plane electron clouds to blend into a single helical network.
Peer-reviewed study confirms the molecule switches under voltage
Science formally validated the findings in March, showing that high-voltage electrical pulses between 4.5 and 5 volts cleaved eight chlorines from precursor molecules resting on a two-layer salt film at 5 K. Atomic force microscopy with a carbon-monoxide tip proved that the carbon backbone warped out of plane by roughly 24 degrees, while scanning tunneling microscopy tracked a helical electron density that matched theoretical predictions. Tipping the voltage past 210 millivolts allowed the microscope to drive the molecule back and forth between two mirror-image singlets and a flat triplet form.
Independent chemists separate molecular reality from computing claims
Follow-up reporting pushed back against exaggerated narratives that quantum hardware had directly discovered the molecule or proven quantum entanglement. Chemistry World pointed out that the molecules exist only when individually crafted under extreme refrigeration at minus 268 degrees Celsius on salt in vacuum, with no bulk production in sight. Concurrently, the computational team published a separate paper proving their quantum calculation could scale from 72 qubits across 36 orbitals up to 100 qubits across 50 orbitals, showing that the 100-qubit milestone was a computing benchmark rather than the original molecular analysis.
Viral online claims blur experimental proof with quantum hype
After appearing in the permanent print archive of Science in May, the finding resurfaced on social media platforms in August with inaccurate claims that a quantum computer had proved quantum entanglement inside the molecule. The historical record shows the experimental discovery relied directly on scanning microscopy and traditional chemical theory, with quantum hardware acting strictly as a numerical check on electron interactions. Independent teams have yet to measure the theoretical quantum phase shifts predicted for the ring, leaving its deeper quantum properties open to future tests.
Where things stand
The molecule C13Cl2 stands as the first verified chemical structure displaying a half-Möbius electron topology. On an insulating sodium chloride surface, the non-planar chiral singlet state represents the thermodynamic ground state, resting about 0.44 electron-volts below the flat triplet state. Applying electric bias above 210 millivolts allows researchers to reversibly flip the molecule between its two mirror-image configurations and the triplet form.
Strict technical constraints limit the system. The compound has been generated only atom by atom under ultra-high vacuum at 5 K, meaning bulk synthesis remains unachieved. Quantum processors served as an advanced computational validation tool rather than an empirical sensor of entanglement, and proposed electronic effects such as a quarter-turn Berry phase await independent verification.