I'm having my players do a planar treasure hunt to find all the seven chaos emeralds. The party includes a LG dragonborn champion fighter, a LN human conquest paladin, a NG triton artificer, a CN changeling thief rogue, and a LE hunter ranger. They are all level 6 (except for the ranger, he is lv5). My problem is, I have no idea which planes to put the emeralds, any ideas?

• The space emerald, allowing travels of great distances in an instant, could be located in the Ethereal plane.
• The mind emerald. which could enhance one's intelligence and control the minds of others, seems to feel natural in the Astral plane.
• The reality emerald, with its ability to alter the order of the universe and create great chaos, might be hidden away on the plane of Pandemonium.
• The time emerald... well, the clockwork plane of Mechanus seems perfect to me.
• The power emerald represents raw power and that makes me imagine it in the Abyss with demon lords fighting endlessly to control it and use its power for their own petty gain.
• The soul emerald, unlike the others, is right here on the material plane. Unfortunately, it is the phylactery of a lich and is therefore very closely guarded.
• The ego emerald, whose purpose is shrouded in shadow and mystery, is hidden away deep in the Shadowfell

Once you acquire the various emeralds, solving your problems would be a snap.

Is there a reason you want to borrow from another franchise? It's not a bad idea or anything, it's just unoriginal and uninspired. I'd go for the rod of seven parts myself, or I'd cobble something together like the canopic jars of the grand pharao.

I'm not sure what the chaos emeralds are supposed to do, but chaos sounds like a fun thing to introduce to the clockwork nirvana of mechanus.

It doesn't matter. Sonic always gets them.

Coincidentally there are 7 chaos aligned outer planes as detailed in the DMG.