Speckled Alder – Alnus incana

Samarium(III) fluoride (Sm F₃) 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:^[1]

SmCl₃ + 3 HF → SmF₃↓ + 3 HCl

Sm₂(CO₃)₃ + 6 HF → 2 SmF₃ + 3 H₂O + 3 CO₂↑

Samarium(III) fluoride can also be produced by hydrothermal reaction of samarium nitrate and sodium fluroborate at 200 °C.^[2]

Properties

Chemical

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

{\mathsf {4SmF_{3}+C\ {\xrightarrow {2000^{o}C}}\ 4SmF_{2}+CF_{4}}}

{\mathsf {2SmF_{3}+Sm\ {\xrightarrow {1800^{o}C}}\ 3SmF_{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.^[3]

References

^ 王亚军, 刘前, 索全伶, 等. 稀土氟化物的沉淀方法及组成研究[J]. 稀土, 2000, 21(1):14-18.
^ 孙元平, 贾佩云, 王芳, 等. 水热条件下稀土氟化物形貌的规律性生长[J]. 中国陶瓷, 2013(6).
^ Rotereau, K; Daniel, Ph; Desert, A; Gesland, J Y (1998-02-16). "The high-temperature phase transition in samarium fluoride, : structural and vibrational investigation". Journal of Physics: Condensed Matter. 10 (6): 1431–1446. Bibcode:1998JPCM...10.1431R. doi:10.1088/0953-8984/10/6/026. ISSN 0953-8984. S2CID 250841162.

[1] 王亚军, 刘前, 索全伶, 等. 稀土氟化物的沉淀方法及组成研究[J]. 稀土, 2000, 21(1):14-18.

[2] 孙元平, 贾佩云, 王芳, 等. 水热条件下稀土氟化物形貌的规律性生长[J]. 中国陶瓷, 2013(6).

[3] Rotereau, K; Daniel, Ph; Desert, A; Gesland, J Y (1998-02-16). "The high-temperature phase transition in samarium fluoride, : structural and vibrational investigation". Journal of Physics: Condensed Matter. 10 (6): 1431–1446. Bibcode:1998JPCM...10.1431R. doi:10.1088/0953-8984/10/6/026. ISSN 0953-8984. S2CID 250841162.

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