Lanthanum cuprate

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]

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

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]