LK-99

Also known as Lee‒Kim‒1999, LK99

Chemical data

Formula: CuO25P6Pb9
Molecular weight: 2510 g/mol
IUPAC name: copper;nonakis(lead(2+));oxygen(2-);hexaphosphate
SMILES: [O-2].[O-]P(=O)([O-])[O-].[O-]P(=O)([O-])[O-].[O-]P(=O)([O-])[O-].[O-]P(=O)([O-])[O-].[O-]P(=O)([O-])[O-].[O-]P(=O)([O-])[O-].[Cu+2].[Pb+2].[Pb+2].[Pb+2].[Pb+2].[Pb+2].[Pb+2].[Pb+2].[Pb+2].[Pb+2]
InChIKey: KZSIWLDFTIMUEG-UHFFFAOYSA-A
Polar surface area: 519 Å²
H-bond donors: 0
H-bond acceptors: 25
Formal charge: 0

via PubChem

~19 min read

Encyclopedic overview

17 sections

Contents

Chemical properties and structure
Synthesis
Physical properties
Proposed mechanism for superconductivity
Proposed absence of superconductivity
Publication history
Scholarly articles and preprints
Other discussion by authors
Response
Public response
Replication attempts
Selected experimental studies
Theoretical studies
See also
References
Further reading
External links

LK-99 also called PCPOSOS, is a gray–black, polycrystalline compound, identified as a copper-doped lead‒oxyapatite. A team from Korea University led by Lee Sukbae () and Kim Ji-Hoon () began studying this material as a potential superconductor, and in July 2023 published preprints claiming that it acted as a room-temperature superconductor at temperatures of up to at ambient pressure.

Many different researchers attempted to replicate the work, and were able to reach initial results within weeks, as the process of producing the material is relatively straightforward. By mid-August 2023, the consensus was that LK-99 is not a superconductor at room temperature, and is an insulator in pure form.

Excerpted from Wikipedia’s “LK-99” article, available under the CC BY-SA 4.0 licence.