I'm trying to make a transcription of the song Rio by Duran Duran, but I'm having difficulties. For instance, it seems to have both a C and C# chord, no major or minor scale seems to have both these chords in it
Also, I find that tabs or chords on other sites vary wildly when transcribing this song. See for instance these two tabs:
Both of these tabs are inaccurate. The verse goes like
Minor: i - VI6 - iv7 - VI - i - VI6 - IV6 - VI (common practice style)
Minor: i - ♭VI6 - iv7 - ♭VI - i - ♭VI6 - IV6 - ♭VI (popular music style)
Em - C/E - Am7 - C - Em - C/E - A/C♯ - C (modern notation)
The IV6 chord must be borrowed from the Dorian mode, other modes will give a supermodal chord in the relative Major key.
Hhmm sounds like you could be right. I created this TheoryTab out of it: