Chloride substitution induced by mechano-chemical reactions between NaBH4 and transition metal chlorides

▸ The metathesis reaction between NaBH4 and TM-chlorides does not proceed under all experimental conditions. ▸ Cl− to BH4− ion substitution is systematically induced by ball milling in NaBH4 samples when using a variety of transition metal (TM) chlorides. ▸ This leads to Na(BH4)1−xClx borohydrides, with x ranging from x = 0.69 to 0.92 depending on the TM. ▸ Our experimental work evidences the difficulties encountered for the successful synthesis of mixed metal borohydrides by mechano-chemical methods, which remain a challenge.