Synonyms: 6-[[(4r,5s,6s)-2-carboxy-6-[(1r)-1-hydroxyethyl]-4-methyl-7-oxo-1-azabicyclo[3.2.0]hept-2-en-3-yl]thio]-6,7-dihydro-5h-pyrazolo[1,2-a][1,2,4]triazol-4-ium inner salt;(4R,5S,6S)-3-(6,7-dihydro-5H-pyrazolo[1,2-a][1,2,4]triazol-4-ium-6-ylsulfanyl)-6-[(1R)-1-hydroxyethyl]-4-methyl-7-oxo-1-azabicyclo[3.2.0]hept-2-ene-2-carboxylate;6-({(4R,5S,6S)-2-carboxy-6-[(1R)-1-hydroxyethyl]-4-methyl-7-oxo-1-azabicyclo[3.2.0]hept-2-en-3-yl}sulfanyl)-6,7-dihydro-5H-pyrazolo[1,2-a][1,2,4]triazol-4-ium