Griffiths, W. Richard published the artcileThe mass spectra of phosphonyl compounds. Part 3. Dimethyl- and diethylalkane and substituted-methane phosphonates, Name: Diethyl (bromomethyl)phosphonate, the publication is Phosphorus and Sulfur and the Related Elements (1978), 5(1), 101-6, database is CAplus.
The electron impact spectra of 28 related phosphonates were determined Et, Me2CH, and Me3C groups which are bound directly to P, fragment to the corresponding alkenes; similar Me2CH, Me3C groups in the di-Me esters also fragment to ethylene and propene, resp., i.e., the P-alkyl rearranges with transfer of the elements of a Me group to the P ion. The di-Et alkenephosphonates undergo double H rearrangements of an ethoxy group to give dihydroxyphosphonium ions. The di- and trihydroxyphosphonium ions have a characteristic fragmentation which involves loss of water. This characteristic has been used as evidence for the rearrangement of a phosphacylium ion to a dihydroxyphosphonium ion.
Phosphorus and Sulfur and the Related Elements published new progress about 66197-72-6. 66197-72-6 belongs to bromides-buliding-blocks, auxiliary class Aliphatic Chain, name is Diethyl (bromomethyl)phosphonate, and the molecular formula is C5H12BrO3P, Name: Diethyl (bromomethyl)phosphonate.
Referemce:
https://en.wikipedia.org/wiki/Bromide,
bromide – Wiktionary