Rubidium fluoride

Cubic

Rb, F

Rubidium (I ) fluoride

White odorless solid

Fixed

3.58 g · cm -3

795 ° C

1410 ° C

1306 g · l -1 in water at 18 ° C

1,397

Attention

2.5 mg · m -3 ( as fluoride)

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Is a chemical bond between rubidium and rubidium fluoride. It does not happen in nature and readily dissolves in water. There is a scoring of the fluoride salt crystallizes in the sodium chloride structure.

Production and representation

Rubidium can be obtained by reaction of hydrogen fluoride with rubidium or rubidium hydroxide and subsequent drying:

Properties

It is a white crystalline material having a cubic crystal structure that is similar in appearance to the very common salt ( NaCl). The crystals belong to the space group Fm3m with lattice parameter a = 565 pm, and four formula units per unit cell. The refractive index of the crystals is nD = 1.398. Rubidium colored flame ( Bunsen burner ) purple or magenta ( spectral analysis ).

Rubidium forms two different hydrates, a sesquihydrate with the stoichiometric composition 2RbF · 3H2O and a Drittelhydrat with the composition 3RbF · H2O.

Besides simply rubidium and an acid with the formula rubidium HRbF2 is known which can be prepared by reaction of hydrogen fluoride and rubidium. The compounds H2RbF3 and H3RbF4 have also been synthesized.

The solubility in acetone of 0.0036 g / kg at 18 ° C, and 0.0039 g / kg at 37 ° C.

The standard enthalpy of rubidium is ΔfH0298 = -552.2 kJ · mol -1, the free standard enthalpy of -520.4 kJ · mol ΔG0298 = 1, and the molar Standardentropie S0298 = 113.9 J · K-1 · mol -1. The enthalpy of solution of rubidium was determined to -24.28 kJ / mol.

Safety

On the basis of the fluoride contained a contact with skin and if swallowed when dealing with rubidium to avoid.