Usually nanoparticles are not atomically precise and thus of little use for atomically precise manufacturing.
For something to qualify as a "nanoparticle" the following criteria must be met:
- it must be a pieces of matter in the solid state
- it must have a size smaller than a micrometer (= 1000 nanometers)
- it must not be too strongly bond to identical particles and it must not be too strongly bond to a substrate.
=> among others (e.g. high surface area makes high reactivity) easy spilling due to unbondedness is a reason why toxicity considerations are so important for nanoparticles
Atomically precise nanoparticles
- produced by chemical means
- containing metals (e.g. gold)
- crystalline (also called: "nano crystals") - otherwise they most likely get called otherwise.
- Atomically precise gold nanocrystal molecules with surface plasmon resonance  - by Huifeng Qian, Yan Zhu, and Rongchao Jin - Department of Chemistry, Carnegie Mellon University, Pittsburgh, PA 15213
- [Todo: Hunt for relevant work about atomically precise nanoparticles]