 A bare proton , H + , cannot exist in solution or in ionic crystals because of its unstoppable attraction to other atoms or molecules with electrons . Except at the high temperatures associated with plasmas , such protons cannot be removed from the electron clouds of atoms and molecules , and will remain attached to them . However , the term ' proton ' is sometimes used loosely and metaphorically to refer to positively charged or cationic hydrogen attached to other species in this fashion , and as such is denoted " H + " without any implication that any single protons exist freely as a species . 
