A metallic phase was discovered in 1990 when solid oxygen is subjected to a pressure of above 96 GPa and it was shown in 1998 that at very low temperatures, this phase becomes superconducting.
En 1990 descubriuse unha fase metálica cando o osíxeno sólido se somete a unha presión superior a 96 GPa e demostrouse en 1998 que a temperaturas moi baixas se converte en supercondutor.