Before Winkler published his results on the new element, he decided that he would name his element neptunium, since the recent discovery of planet Neptune in 1846 had similarly been preceded by mathematical predictions of its existence.
Înainte de publicarea rezultatelor privind noul element, Winkler a decis ca elementul să fie numit neptunium, din moment ce recenta descoperire a planetei Neptun în 1846 a fost anunțată de predicții matematice.