Yttrium barium copper oxide

Yttrium barium copper oxide
Names
	IUPAC name barium copper yttrium oxide
	Other names YBCO, Y123, yttrium barium cuprate
Identifiers
CAS Number	107539-20-8 ;
3D model (JSmol)	Interactive image;
ChemSpider	17339938;
ECHA InfoCard	100.121.379
EC Number	619-720-7;
PubChem CID	21871996;
CompTox Dashboard (EPA)	DTXSID90148081 ;
	InChI InChI=1S/2Ba.2Cu.7O.2Y/q4+2;7-2;2*+3 Key: YMLQHJRUACGKIM-UHFFFAOYSA-N;
	SMILES [O-2].[O-2].[O-2].[O-2].[O-2].[O-2].[O-2].[Cu+2].[Cu+2].[Y+3].[Y+3].[Ba+2].[Ba+2];
Properties
Chemical formula	YBa2Cu3O7
Molar mass	666.19 g/mol
Appearance	Black solid
Density	6.4 g/cm3
Melting point	>1000 °C
Solubility in water	Insoluble
Structure
Crystal structure	Based on the perovskite structure.
Coordination geometry	Orthorhombic
Hazards
	GHS labelling:
Pictograms
Signal word	Warning
Hazard statements	H302, H315, H319, H335
Precautionary statements	P261, P264, P270, P271, P280, P301+P312, P302+P352, P304+P340, P305+P351+P338, P312, P321, P330, P332+P313, P337+P313, P362, P403+P233, P405, P501
Related compounds
Related high-Tc; superconductors	Cuprate superconductors
Related compounds	Yttrium(III) oxide; Barium oxide; Copper(II) oxide
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). verify (what is ?) Infobox references

Yttrium barium copper oxide (YBCO) is a family of crystalline chemical compounds that display high-temperature superconductivity; it includes the first material ever discovered to become superconducting above the boiling point of liquid nitrogen [77 K (−196.2 °C; −321.1 °F)] at about 93 K (−180.2 °C; −292.3 °F).

Many YBCO compounds have the general formula Y Ba₂Cu₃O_7−x (also known as Y123), although materials with other Y:Ba:Cu ratios exist, such as Y Ba₂Cu₄O_y (Y124) or Y₂Ba₄Cu₇O_y (Y247). At present, there is no singularly recognised theory for high-temperature superconductivity.

It is part of the more general group of rare-earth barium copper oxides (ReBCO) in which, instead of yttrium, other rare earths are present.