How can borane exist?

*Disclaimer: Sorry if this is a noob question, I am a high school chem student.*


So I was reading my textbook in preparation for the midterm, and it talked about exceptions to the octet rule.


I understand that they exist, and what they are, but how are the chemicals structurally stable? 


I also know that they are reactive, but that still doesn't help.


How do they exist?


I was thinking something like only under high pressure/heat, but I can't find anything to back that up. Amazingly, google hasn't help.


Can somebody please explain?


