| Initial crystal system | tetragonal |
| Final crystal system | cubic |
| Initial space group | I4/mcm |
| Final space group | Pm-3m |
| Direction | Heating |
| Phase transition temperature | 335.0 K |
Hysteresis: 10
| Initial crystal system | cubic |
| Final crystal system | tetragonal |
| Initial space group | Pm-3m |
| Final space group | I4/mcm |
| Direction | Cooling |
| Phase transition temperature | 325.0 K |
Hysteresis: 10
| Initial crystal system | orthorhombic |
| Final crystal system | tetragonal |
| Initial space group | Pnma |
| Final space group | I4/mcm |
| Direction | Heating |
| Phase transition temperature | 169.0 K |
Hysteresis: 7
| Initial crystal system | tetragonal |
| Final crystal system | orthorhombic |
| Initial space group | I4/mcm |
| Final space group | Pnma |
| Direction | Cooling |
| Phase transition temperature | 162.0 K |
Hysteresis: 7
Starting materials: CH3ND3I
Product: Black CH3ND3PbI3 Powder
Description: Preparation of CH3ND3I: React methylamine gas with HI to yield methyl ammonium iodide. Exchange the two H atoms attached to the nitrogen atoms with D by dissolving the salt in 10 ml D2O (99 atom % D), drying under vacuum, and then repeating two more times. The resulting CH3ND3I was estimated to be better than 98 atom% D on the ammonium group. Add material to ~6 g of lead iodide and mix in ~25mL of DMF. Upon stirring, obtain pale yellow clear solution. Warm resulting solution and stir overnight in a N2 glove box. Evaporate solution to dryness under vacuum and wash the resulting black solution with dichloromethane and n-propanol. Isolate using suction drying. Anneal solid in nitrogen in the glove box at 140 °C for 1hr to remove residual solvent.
Comment: MAPbI3 (d3-CH3ND3PbI3)
Method: Neutron diffraction
Description: Samples were loaded into 8mm diameter vanadium cans in a helium glove-box for analysis on the POWGEN diffractometer situated at the Spallation Neutron Source, Oak Ridge National Laboratory. The analyses of the POWGEN data were carried out using the TOPAS refinement package for Rietveld. Heating and cooling rates were 1K/min. Refer to Page 10 Table 2.