Samarium(III) fluoride explained

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:[1]

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:

4SmF3+C \xrightarrow{2000oC 4

SmF2+CF4}

2SmF3+Sm \xrightarrow{1800oC 3

SmF2}

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]

Notes and References

  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 . 10.1088/0953-8984/10/6/026 . 1998JPCM...10.1431R . 250841162 . 0953-8984. subscription .