Rubidium germanium iodide

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Rubidium germanium iodide
Identifiers
3D model (
JSmol
)
  • InChI=1S/Ge.3HI.Rb/h;3*1H;/q+2;;;;+1/p-3
    Key: BMENQWFJSMYCLV-UHFFFAOYSA-K
  • [Ge+2].[I-].[I-].[I-].[Rb+]
Properties
GeI3Rb
Molar mass 538.811 g·mol−1
Melting point 61 °C (decomposes)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

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]

Preparation

Rubidium germanium iodide can be prepared by reacting germanium(II) hydroxide and rubidium iodide in hydroiodic acid:[2]

Ge(OH)2 + RbI + 2 HI → GeRbI3 + 2 H2O

Properties

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]

References