For all negatives and transparencies (whether 5x7, 4x5, 120 roll or sheet, or 35mm) I put my negatives in a 'fold flat' negative sleeve, then put the sleeve into a polyester negative storage sheet before storing the sheet in an archival binder. All of these products can be purchased from Print File or other sources.
The 'fold flat' negative sleeves must be trimmed to fit the negative sheet. Using the negative sleeve eliminates sliding the necked negative into the pocket of the negative sleeve - reducing the possibility of scratching the negative - which has happened in the past.
This is expensive but most of my photography is for archival purposes plus I am not a prolific shooter.