Ammonium with oxygen.....infact with oxygen and hydrogen forms NH4OH...getting +1 on ammonium ion,-2 for oxygen atom. calcium will be obviously +2, dihydrogen phosphate -2 ammonium +1,sulfite -1 manganese +2,sulfate -2 the compounds are ammonium hydroxide,calcium dihydrogen phosphate,ammonium sulfite,manganese sulfate Solution Ammonium with oxygen.....infact with oxygen and hydrogen forms NH4OH...getting +1 on ammonium ion,-2 for oxygen atom. calcium will be obviously +2, dihydrogen phosphate -2 ammonium +1,sulfite -1 manganese +2,sulfate -2 the compounds are ammonium hydroxide,calcium dihydrogen phosphate,ammonium sulfite,manganese sulfate.