What is the structure of SN?

I thought .:S=N:: or ::S=N:. but both were deemed wrong by the homework software we have... help!

I don't know how you are to enter your answers but neither one you wrote carries a charge (both atoms should have a formal charge on both atoms). Also, I don't know if it makes a difference that the ::S or N:: has electrons that look like a double bond. They should be at the top or bottom of the atom. What I'm thinking is that it may be a formatting problem and not a chemistry problem.