| Initial crystal system | unknown |
| Final crystal system | unknown |
| Initial space group | unknown |
| Final space group | unknown |
| Direction | both |
| Phase transition temperature | 168.0 K |
Hysteresis: NIL
| Initial crystal system | unknown |
| Phase transition temperature | K |
Starting materials: HI, CH3NH2, Pb(NO3)2
Product: Partially deuterated MAPbI3
Description: Add concentrated HI to neutralize 20 g of 40% CH3NH2 aqueous solution. Add 7.1 g (0.021 mol) of Pb(NO3)2 solution drop-wise under vigorous stirring at 100°C to the concentrated CH3NH2I solution. Organic crystals form while dripping in the solution. Cool the solution to not below 40°C and filter out the crystals. Wash crystals firstly with n-butanol and then with benzene; subsequently dry crystals in vacuum. Partially N-deuterated samples required for the NMR studies were prepared using D-containing solutions. Refer to Page 413 Experimental.
Comment: Synthesis references: [1] Canadian Journal of Chemistry, 1987, 65(5): 1042-1046 https://doi.org/10.1139/v87-176 [2] D. WEBER. Z. Naturforsch. 33b, 1443 (1978).
Method: 2H and 14N NMR
Description: Measurements were carried out at 8.48 T with a Nicolet 360NB spectrometer using a broad band (16-58 MHz) variable-temperature 10 mm probe supplied by Nicolet. The 2-H and 14-N frequencies were 55.427 and 26.083 MHz, respectively. Refer to Page 414 Results section Existence of transitions subsection.