[{"from": "human", "value": "Based on the given information, design a molecule that meets the desired specifications. The molecule is a selenium hydride and a mononuclear parent hydride. It has a role as an Escherichia coli metabolite and a mouse metabolite. It is a conjugate base of a selenonium. It is a conjugate acid of a selanide."}, {"from": "gpt", "value": "[SeH2]"}]