hydron proton (1)1H(+) (1)H(+) Nuclear particle of charge number +1, spin 1/2 and rest mass of 1.007276470(12) u. chebi_ontology proton proton KEGG:C00080 CHEBI:24636 [1H] protium(1+) [1H+] p(+) GPRLSGONYQIRFK-FTGQXOHASA-N 1.007 CAS:12408-02-5 +1 1.00728 InChI=1S/p+1/i/hH p nucleon molecule