The present invention relates to a kind of formula (I) (1R,2S,5R) sulfonyloxy-1-7- oxos-6-,6- diazabicyclos [3.2.1] sodium salt of octane -2- formamides, in hydration or anhydrous crystal enantiomeric forms. The compound of the present invention can be used as drug, especially beta-lactamase inhibitor.本發明涉及一種式(I)的(1R,2S,5R)-7-氧代-6-磺酰氧基-1,6-二氮雜雙環[3.2.1]辛烷-2-甲酰胺的鈉鹽,其呈水合或無水結晶對映異構體形式。本發明的化合物可用作藥物,尤其是β-內酰胺酶抑制劑。