The following is a list of chemical purification methods for starting materials that slowly oxidize, hydrate, or equivalent bad things when stored in air.
| Material | Problem | Purification |
| CaO | Hydrates (to Ca(OH)2) Carbonates (to CaCO3) |
Heat 1200 C, 12 hr, Air |
| DyN | Decomposes | Not Known |
| Fe2O3 | Decomposes | γ-Fe2O3: Heat 300 C, 4 hr, O2 flow α-Fe2O3: Heat 450 C, 4 hr, O2 flow |
| LaN | Decomposes | Not Known |
| La2O3 | Hydrates | Heat 900 C, 12 hr, Air |
| Li2CO3 | Hydrates | Heat c.a. 120 C, overnight (drying oven) |
| MnO2 | Reduces | Not Known |
| Mn2O3 | Stable | Heat MnO2 900 C, 12 hr, Air |
| MnO | Oxidizes | Heat Mn2O3/MnO2 1000 C, 12 hr, 5%H2/Ar |
| MoO2 | Oxidizes | Heat MoO2/MoO3 550 C, 5%H2/Ar, until reduced (overnight+) |
| Na2CO3 | Hydrates | Heat c.a. 120 C, overnight (drying oven) |
| NbO | Oxidizes | Not Known |
| NbO2 | Oxidizes | From Nb2O5: Heat 900-1000 C, 12 hr, under 5%H2/Ar From NbO: Heat 1200 C, 12 hr, Air, then follow above steps |
| Nb2O5 | Hydrates | Heat 1000 C, 12 hr, Air |
| NdN | Decomposes | Not Known |
| PbO2 | Hydrates,Decomposes | Heat 535 C, 1 hr, O2 |
| RhO2 | Hydrates,Decomposes | Heat 550 C, 4 hr, O2 |
| RuO2 | Hydrates | Heat 700 C, 4 hr, Air |
| VN | Decomposes | Not Known |
| V2O3 | Oxidizes/Hydrates | Heat 60 C/hr to 1100 C, 24 hr, 5%H2/Ar |
| VO2 | Oxidizes/Hydrates | Heat stoichiometric, ground V2O3 and V2O5 in quartz tube at 900-1000 C until done |
| WO2 | Oxidizes | Heat 700 C, 1-3 hr, 5% H2/Ar (small sample size essential, multiple mixings/heatings necessary) |
| YN | Decomposes | Not Known |
| Y2O3 | Hydrates | Heat 900 C, 12 hr, Air |
| ZnS | Oxidizes | Heat 400 C, 16 hr, CS2/Ar |