!!!! Hexamethyl trioxane

https://aip.scitation.org/doi/abs/10.1063/1.437009 @@ Trott et al: ionization of acetone and oligomers.

https://aip.scitation.org/doi/abs/10.1063/1.479554 @@ Mair et al: may use trimer cation.

https://link.springer.com/article/10.1016/1044-0305(91)80004-Q @@ Aviyente et al: clusters of acetone trimer + H2O

https://www.sciencedirect.com/science/article/abs/pii/S0301010412002674 @@ Guan et al: IR-VUV spectra of acetone oligomers

https://doi.org/10.1002/apmc.1996.052360101 @@ Cataldo: self‐polymerization of acetone

https://link.springer.com/article/10.1007/s10563-012-9141-4 @@ Tago et al: pholone and iso-pholone called "acetone trimers" but are tautomers thereof.

https://pubchem.ncbi.nlm.nih.gov/compound/21579391 @@ PubChem: 3,3,5,5,6,6-Hexamethyl-1,2,4-trioxane spectrum.

https://spectrabase.com/spectrum/26EYxCgaEoa @@ SpectraBase: 3,3,5,5,6,6-Hexamethyl-1,2,4-trioxane spectrum.

https://mits.nims.go.jp/MatNaviSearch/?_e=i&w=1&m=p&tx=%22Monomer%22&by=1&cva=on&lot=and&sy=01&o=5000 @@ NIMS-JP:  MID: M1871298 Systematic Name: " 2,2,4,4,6,6-hexamethyl-1,3,5-trioxane"

http://www.chemdatas.com/Product/PID140817CAS68580-04-1E.html @@ ChemDatas.com: claims that CAS is 68580-04-1