Is 868MHz a standard frequency? Can I use an arduino to send/receive data?

In the FCC regulatory domain, Part 15 devices can share a band with amateurs, but you can't squeal if you get clobbered. or, you can, but so what.

except where I live. where I live amateurs can't use the 902-928 band, but Part 15 users can. So I just stay away from it because explaining it gives everyone a headache