Samarium(III) fluoride

Samarium(III) fluoride (SmF₃) is a slightly hygroscopic solid fluoride. Conditions/substances to avoid are: open flame, moisture, strong acids.

Preparation

Samarium(III) fluoride can be obtained by reacting SmCl₃ or Sm₂(CO₃)₃ with 40% hydrofluoric acid:

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Samarium(III) fluoride can also be produced by hydrothermal reaction of samarium nitrate and sodium fluroborate at 200 °C.

Properties

Chemical

Samarium(III) fluoride reacts with some reducing agents at high temperatures to obtain samarium(II) fluoride:

$\mathrm{𝟦}𝖲𝗆{𝖥}_{\mathrm{𝟥}}\mathsf{+}𝖢\stackrel{2000^{o}C}{\to }\mathrm{𝟦}𝖲𝗆{𝖥}_{\mathrm{𝟤}}\mathsf{+}𝖢{𝖥}_{\mathrm{𝟦}}$

$\mathrm{𝟤}𝖲𝗆{𝖥}_{\mathrm{𝟥}}\mathsf{+}𝖲𝗆\stackrel{1800^{o}C}{\to }\mathrm{𝟥}𝖲𝗆{𝖥}_{\mathrm{𝟤}}$

Physical

At room temperature, samarium(III) fluoride has orthorhombic structure with space group Pnma – β-YF₃ type with lattice constants a = 666,9 pm, b = 705,9 pm, c = 440,5 pm. Above 495 °C, it has the rhombohedral LaF₃ structure (space group P3cl) – with lattice constants a = 707, c = 724 pm.