Large portion of very back top left molar is missing and black. Would it be fixable with a crown of some sort?

If your tooth is broken, it is important that you see your dentist right away.  Most likely, you will be able to have a restoration placed to fix the broken tooth.  It is important that your dentist examines this tooth and gives you your options for the best possible treatment.  Get this taken care of right away because at this point you are running the risk of further fracturing your tooth, or nerve involvement.

As others have mentioned, you need to see a dentist as soon as possible. You may just need a new filling and perhaps a crown. Depending upon how far the broken edge of the tooth goes, you should also consider seeing a periodontist for a crown lengthening procedure. This will allow the dentist to have more visible tooth structure for a better crown and a better margin. 

Hi, thanks for sending your question. Its important for your tooth to be examined by a dentist in order to determine the best treatment possible. At this point the chance of further fracture and involvement with the nerve is possible, therefore it would be in your best interest to take care of this tooth as soon as possible. all the best,

Of course, without seeing an x-ray I can't truly give you a definite opinion. However, typically what you're seeing is black that is from a silver filling that's in the tooth and decay that also may exist. Teeth that fracture often do so the way you describe and most times can have a crown placed to restore it. If it does need to be extracted, you could have it done under local anesthetic without needing to be sedated. If that's the case, you should have it removed by an Oral Surgeon.