Sodium Nitroferricyanide Hi, I was wondering if someone could help me out with the aforementioned compound. I was meandering my way through wikipedia while at work today, and I came across nitroprusside while in the hemoglobin article. The article lists the molecule as a dianion, but I can't for the life of me find where the negative charge(s) should be on the molecule (in fact, it looks like there are two positively charged atoms there -- the nitrogen and oxygen of the nitric oxide group). I am usually pretty good with strictly organic molecules, but bio-inorganics are somewhat unfamiliar to me. I'm guessing it will have to do with the iron atom, but I am really just speculating. There is an image at the wikipedia article.