Supplementary Figure 4: Different HF cylinder setups.

a Dual valve setup with the gas outlet connected to a gooseneck eductor tube sourcing HF from the gas phase and the liquid outlet connected to a full-length eductor tube (FLET) sourcing HF from the liquid phase. The FLET outlet will deliver HF significantly faster than the gooseneck outlet. b Single gooseneck eductor tube - the cylinder can come with a N2 layer, which need to be pulled off through the HF apparatus and CaO trap before HF can be utilized. We recommend a gooseneck eductor tube setup without N2 layer. Do NOT use a FLET HF cylinder with a N2 layer since this delivers HF under pressure and is not compatible with the HF apparatus.