maybe it would be called a 12th chord. the cool sound that joni mitchell uses throughout court and spark is done by playing a 5th in the left hand and then whatever that 5th note is, play the 2cnd inversion of that note as a triad. like if it was C and G in the left hand then add B, D G in the right hand. what’s especially great about the suspended sound is no commitment to anything that resolves, you can play them chromatically or move them around randomly and they always land with the same stimulating presence and disinclination to say let us resolve this way or that way.