Rubidium germanium iodide is a ternary halide of rubidium and germanium, with the chemical formula RbGeI3.
It is being considered as a potential counterpart to the toxic CH3NH3PbI3 for photovoltaic applications.
[1] Rubidium germanium iodide can be prepared by reacting germanium(II) hydroxide and rubidium iodide in hydroiodic acid:[2] Rubidium germanium iodide is polymorphic with various distorted perovskite-like structures, reflecting the influence of the "non-bonding" pair of electrons on the centre of Ge2+.
[3] At room temperature, rubidium germanium iodide has a black, cubic perovskite form; between -29 °C and -52 °C a black rhombohedral form; a bordeaux-red orthrhombic perovskite form between -52 °C and -92 °C; and a lemon-yellow orthorhombic form below -92 °C.
[4]