The lack of (a minor or a major) 3rd in a chord creates an open sound while the dissonance between the 4th and 5th and root creates tension. The two most common types are the suspended second (sus2) and the suspended fourth (sus4). In a sus2 chord, the second note of the scale is used instead of the third, while in a sus4 chord, the fourth note is used.

They are called "suspended" because they contain a note that is "suspended" from a previous chord and then resolved to a new note in the following chord. A suspended 4 chord is using the interval 1,4,5. A suspended 2 chord is using the the interval 1,2,5.

Suspended Chords on Mandolin

What are the notes in C natural minor?

The notes of the C natural minor scale are C, D, E♭, F, G, A♭, B♭ and its formula is1, 2, ♭3, 4, 5, ♭6, ♭7.