Fm chord inversions
Fm/Ab and Fm/C are the first and second inversions of the F minor. This means that the bass tone is shifting from F to Ab or C.
Fm/Ab
Fm/C
Try in a chord progression
Fm/Ab - Gm/Bb - Eb
Fm - Fm/C - Bbm
Comments
When stumble upon these chord names, you can choose to ignore the alternate bass note and play the regular F minor. It will always sound ok, but it may lack some subtle additions to the sound. Notice that the diagram version of Fm/C presented above is similar with the Fm barre shape with the bass note on the fifth string except that the sixth string has been included.
Alternative fingerings
Another option for Fm/Ab is XXX111. Fm/C can be played in first position as X33111.
Theory of the Fm/Ab and Fm/C chords
Both chords consist of the notes F, Ab, C. The difference is that the order of notes shifts. A flat is the bass note in the first inversion and C is the bass note in the second inversion.
Alternative chord names
Fm/Ab is identical with Ab6(no5).
See also Fm7 inversions
Chord construction
Fm x -x - F - Ab - C - F
Fm/Ab x -x - Ab - C - F - Ab
Fm/C C - F - C - F - Ab - C
Guitar versions of the chord
Notes in chord
Fm F - Ab - CFm/Ab Ab - C - F
Fm/C C - F - Ab
Only the order of notes differs