DSC and X-Ray Studies on the Phase Transitions in (NH₄)₃Li(SO₄)₂

Abstract

Triammonium lithium disulfate NH(₄)₃Li(SO ₄)₂ was crystallized by evaporating the aqueous solution at room temperature. The phase transition and the crystal structure at room temperature were investigated by means of differential scanning calorimetry (DSC) and single-crystal X-ray diffraction, respectively. As a result, thermal anomalies relating to phase transitions were observed at 221 K, 286 K and 458 K. At room temperature, NH(₄)₃Li(SO₄)₂ belonged to the monoclinic space group P2₁ (Z = 2) and had lattice constants of a = 8.78105(5) Å, b = 5.2823(2) Å, c = 9.1331(5) Å, β = 90.0782(9)°. The R factor converged to 0.0477.

Keywords:

• A ₃ B(XY ₄)₂ family
• (NH₄)₃Li(SO₄)₂
• phase transition
• differential scanning calorimetry
• single-crystal X-ray diffraction

PACS #:

• 61.66.Fn
• 05.70Fh
• 81.70.Pg
• 61.05.cp

Acknowledgments

Authors would like to thank Dr. E. Ishikawa of Chubu University for her valuable discussion on X-ray analysis. This research is partly sponsored by Advance Electric Co., Inc.

Notes

The general temperature factor expression: exp (−2π²(a*² U ₁₁ h ²+ b*² U ₂₂ k ²+ c*² U ₃₃ l ²+ 2a*b*U ₁₂ hk + 2a*c*U ₁₃ hl + 2b*c*U ₂₃ kl)).