A Refinement of the Hg2F2 Structure by the Use of NMR Data

Abstract

The crystal structure of Hg₂F₂ was studied in works.^1,2 The Hg₂F₂elementary cell of the tetragonal syngony with a=3.66 Å and c=10.89 Å contains two formula units, the space-group being 14/mmm. Hg₂F₂ belongs to those types of structures which possess one non-fixed coordinate (z_F and zHg); hence, the position of the fluorine nuclei may be determined from the value of the second moment of the NMR spectrum of ¹⁹F for powder sample.³ In this case it is ostensibly important, inasmuch as determining the positions of fluorine nuclei near the heavy mercury atoms presents a difficulty for X-ray analysis.