“…For these syntheses, the selenium sources often applied can be either commercial reactants, such as sodium selenite (NaSeO 3 ) [11], or in situ yielded selenium species, like sodium selenosulfide (NaSeSO 3 ), formed from the reduction of elemental selenium by sodium sulfite [12]. Another selenium source usually used is sodium hydrogen selenide (NaHSe) obtained from reduction of elemental selenium by sodium borohydride (NaBH 4 ) [13,14].…”