Lanthanum cuprate

Lanthanum cuprate

Identifiers
CAS Number	12053-92-8
3D model (JSmol)	Interactive image
PubChem CID	159645064
InChI InChI=1S/Cu.2La.4O/q+2;2*+3;4*-2 Key: VTQXYJGFVOFCDC-UHFFFAOYSA-N
SMILES [O-2].[O-2].[O-2].[O-2].[Cu+2].[La+3].[La+3]
Properties
Chemical formula	CuLa2O4
Molar mass	405.353 g·mol−1
Appearance	solid
Density	7.05 g/cm3
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Lanthanum cuprate usually refers to the inorganic compound with the formula CuLa₂O₄. The name implies that the compound consists of a cuprate ([CuO_n]^2n-) salt of lanthanum (La³⁺). In fact it is a highly covalent solid. It is prepared by high temperature reaction of lanthanum oxide and copper(II) oxide follow by annealing under oxygen. ^[1]

The material adopts a tetragonal structure related to potassium tetrafluoronickelate (K₂NiF₄), which is orthorhombic. ^{[1] [2]} Replacement of some lanthanum by barium gives the quaternary phase CuLa_1.85Ba_0.15O₄, called lanthanum barium copper oxide. That doped material displays superconductivity at −243 °C (30.1 K), which at the time of its discovery was a high temperature. This discovery initiated research on cuprate superconductors and was the basis of a Nobel Prize in Physics to Georg Bednorz and K. Alex Müller. ^[3]

References

1. Longo, J.M.; Raccah, P.M. (1973). "The structure of La₂CuO₄ and LaSrVO₄". Journal of Solid State Chemistry. 6 (4): 526–531. Bibcode:1973JSSCh...6..526L. doi:10.1016/S0022-4596(73)80010-6.
2. Grande, B.; Müller-Buschbaum, Hk.; Schweizer, M. (1977). "Über Oxocuprate. XV zur Kristallstruktur von Seltenerdmetalloxocupraten: La₂CuO₄, Gd₂CuO₄". Zeitschrift für Anorganische und Allgemeine Chemie. 428: 120–124. doi:10.1002/zaac.19774280116.
3. Bednorz, J. G.; Müller, K. A. (1986). "Possible High T_c Superconductivity in the Ba-La-Cu-O System". Zeitschrift für Physik B: Condensed Matter. 64 (2): 189–193. Bibcode:1986ZPhyB..64..189B. doi:10.1007/BF01303701. S2CID   118314311.