Polymeres are not the main interest in advanced atomically precise manufacturing since they are not stiff and diamondoid. Some of them may be useful in the early stages of the path to APM. They may play some role in some products of advanced atomically precise technology though like in thermomechanical energy converters. Introducing polymers into advanced AP systems (that are mainly crystolecule based) means introducing weak spots. Radiation and heat have a higher chance to break a long chain than a solid crystolecule brick. See: Consistent design for external limiting factors
- Inorganic polymers: Usually not found in nature. They can have some unusual properties
- Conductive polymers: Common polymers are usually electrically isolating. Conductive polymers might be useful in early stages of bootstrapping of APM (e.g. for electrostatic actuation)
- Artificial foldamers (the name implies their defining self folding property): beside common biological foldamers artificial foldamers are very likely to play a major role in the development of advanced APM (gem gum technology).
- Polymers with combinations of the precedingly described properties.
Unusual transition element oxides
Transparent volatile liquid metal oxides (/rusts). Note that those are highly toxic.
Rather inert compounds with fluorine
- Sulfur hexafluoride
- Nitrogen trifluoride
Other compounds with unusual properties
- Carbon disulfide
- Diphosphane (leave to Wikipedia - please come back again)
- Trimethylphosphine (leave to Wikipedia - please come back again)
- Carbon suboxide (leave to Wikipedia - please come back again)
Carbon suboxide has a low energy state in earth’s oxidative environment and can be polymerized to a solid that could easily be stored by today’s means. When chemomechanical converters will become available there most likely will be better storage methods for depleted energy available though. So its just a curiosity. Note: Somewhat unintuitively the compound C2O2 (ethylene dione) is very unstable. It has a short lifetime even at low temperatures. This is one of the more subtel instances where one can see that the "periodic table as construction kit" metaphor must often be taken with a grain of salt.
Compounds dominantly containing nitrogen
Those are usually quite unstable to explosive.
Grey α-tin: Tin has a fully nonmetallic form that takes on the more sparse crystal structure of silicon due to covalent bond coordination. Replacing some silicon atoms in a silicon quartz or silicon carbide crystal with tin is likely to lead to stable structures with maybe desirable properties. https://en.wikipedia.org/wiki/Tin_pest
Xenon dioxide: Under high pressure xenon supposedly can replace silicon in quartz. It is believed that the theoretically predicted amount of Xenon that is missing in our atmosphere is trapped this way inside the earth. https://en.wikipedia.org/wiki/Xenon_dioxide Highly localized pressure (strained structures) can make (single or multiple substitutions of silicon with xenon) stable at macroscopic ambient pressures. Xenon is not too abundant so applications (whatever they are) are not likely to become widespread.