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GeI2 is trigonal omega-like structured and crystallizes in the trigonal P-3m1 space group. The structure is two-dimensional and consists of three GeI2 sheets oriented in the (0, 0, 1) direction. Ge2+ is bonded to six equivalent I1- atoms to form edge-sharing GeI6 octahedra. All Ge–I bond lengths are 3.03 Å. I1- is bonded in a distorted T-shaped geometry to three equivalent Ge2+ atoms.
GeI2 is Molybdenite-like structured and crystallizes in the hexagonal P-6m2 space group. The structure is two-dimensional and consists of one GeI2 sheet oriented in the (0, 0, 1) direction. Ge2+ is bonded to six equivalent I1- atoms to form distorted edge-sharing GeI6 pentagonal pyramids. All Ge–I bond lengths are 3.07 Å. I1- is bonded in a 3-coordinate geometry to three equivalent Ge2+ atoms.
Computed materials data using density functional theory calculations. These calculations determine the electronic structure of bulk materials by solving approximations to the Schrodinger equation. For more information, see https://materialsproject.org/docs/calculations
The vapor systems GeI2 and I2 and solid GeI4 were analyzed, using Raman spectroscopic techniques. The Raman bands of I2 and GeI4 were confirmed and Raman bands for GeI2 at 230 and 360 cm to the -1 power were reported. The application of the Raman techniques as a temperature probe in vapor transport kinetics was studied, and its feasibility is considered to be very good.
The Raman scattering furnace for investigating vapor transport mechanisms was completed and checked out. Preliminary experiments demonstate that a temperature resolution of plus and minus 5 C is possible with this system operating in a backscatter mode. In the experiments presented with the GeI 4 plus excess Ge system at temperatures up to 600 C, only the GeI4 band at 150 cm superscript minus 1 was observed. Further experiments are in progress to determine if GeI2 does become the major vapor species above 440 C.