See all entries for this property (4 total)
Crystal system: cubic
| a: | 6.316 (±0.001) K |
| b: | 6.316 (±0.001) K |
| c: | 6.316 (±0.001) K |
| α: | 90° |
| β: | 90° |
| γ: | 90° |
Starting materials: Tin (II) iodide, formamidine acetate, HI (aq), argon, nitrogen
Product: Black powder
Description: Dissolve tin(II) iodide (2.235 g, 6 mmol) in flowing argon at 70°C in 4 ml of a concentrated (57% by weight) aqueous HI solution. Dissolve formamidine acetate (0.6246 g, 6 mmol) at room temperature in 1.0 ml of concentrated aqueous hydriodic acid and immediately add to the tin(II) iodide solution (after allowing it to cool), leading to a thick black precipitate. Rinse the formamidinium tube using two additional 0.5-ml portions of hydriodic acid and add to the test tube containing the product, which at all times was kept in an inert atmosphere of flowing argon. Maintain the product in the hydriodic acid solution for 15 min at room temperature, with periodic agitation of the solution, and filter under flowing dry nitrogen gas. Yield was approximately 75% of the theoretical yield. Dry black powder under vacuum at room temperature and store in an argon-filled glovebox, with oxygen and water levels maintained below 1 ppm.
Comment: Single crystal also made. Similar procedure as MASnI3 in D. B. Mitzi, C. A. Feild, Z. Schlesinger, and R. B. Laibowitz, J. Solid State Chem. 114, 159 (1995).
Method: Powder X-ray diffraction
Description: Siemens D5000 CuKalpha radiation, refined using Siemens WIN-METRIC program. Refer to Page 377 X-ray diffraction section.
Crystal system: unknown
| Band gap (optical, diffuse reflectance), eV |
|---|
Starting materials: HC(NH2)2I [from synthesis], SnI2 [from synthesis], distilled HI 57% aqueous (99.95%), H3PO2 (50% aqueous)
Product: Black FASnI3 crystals
Description: Charge 100 ml 2-necked round bottom flask with a mixture of aqueous HI (6.8 ml, 7.58M) and aqueous H3PO2 (1.7 ml, 9.14M). The liquid was degassed by passing a stream of nitrogen through it for 1 min and keeping it under a nitrogen atmosphere throughout the experiment. Dissolve SnI2 (372 mg, 1 mmol) in the mixture upon heating the flask to 120 °C using an oil bath, under constant magnetic stirring, forming a bright yellow solution. Add solid HC(NH2)2I (172 mg, 1 mmol). Evaporate solution to approximately half its original volume by heating at 120 °C. Discontinue stirring and leave the solution to cool back to room temperature. Upon cooling, black rhombic dodecahedral crystals (12 faces) of the title compound were precipitated. Leave crystals to grow for a further 24 h under a nitrogen atmosphere before filtering and washing copiously with degassed EtOH. Yield 70-90%.
Method: Optical-diffuse reflectance
Description: Measurements were performed at room temperature using a Shimadzu UV-3101 PC double-beam, double-monochromator spectrophotometer operating from 200 to 2500 nm. BaSO4 was used as a nonabsorbing reflectance reference. The generated reflectance-versus-wavelength data were used to estimate the band gap of the material by converting reflectance to absorbance data according to the Kubelka−Munk equation: α/S =(1 − R)^2/2R, where R is the reflectance and α and S are the absorption and scattering coefficients, respectively. Refer to Page 9029 Figure 9.