New iodine-apatites: synthesis and crystal structure

Evgeny N Bulanov; Sergey S Petrov; Alexander V Knyazev

doi:10.3906/kim-2102-5

New iodine-apatites: synthesis and crystal structure

Turk J Chem. 2021 Oct 19;45(5):1444-1453. doi: 10.3906/kim-2102-5. eCollection 2021.

Authors

Evgeny N Bulanov¹, Sergey S Petrov¹, Alexander V Knyazev¹

Affiliation

¹ Department of Analytical and Medicinal Chemistry, Faculty of Chemistry, Lobachevsky University, Nizhny Novgorod Russia.

Abstract

The paper describes methods for the preparation of compounds with an apatite structure containing only iodine atoms in the "halogen" position. The crystal structure of the compounds was refined by the Rietveld method. The resulting apatites have a structure with a space group P6₃/m and have the following unit cell parameters: Ba⁴ ^f _1.78(2)Ba⁶ ^h _2.75(2)(PO₄)₃I_0.04(2) (a = 10.18609(34) Å, c = 7.71113(30) Å, V = 692.889(54) Å³, R = 5.448 %), Pb⁴ ^f _1.82(2)Pb⁶ ^h _2.75(2)(PO₄)₃I_0.13(2) (a = 9.87882(18) Å, c = 7.43222(16) Å, V = 628.144(26) Å³, R = 8.533 %), Pb⁴ ^f _1.90(2)Pb⁶ ^h _2.68(2)(PO₄)₃I_0.16(2) (a = 9.87058(48) Å, c = 7.41255(46) Å, V = 625.437(72) Å³, R = 5.433 %). The study of the crystal structure showed a relatively low efficiency of the binding of iodine in the apatite matrix.

Keywords: Rietveld refinement; apatite; crystal structure; synthesis; Iodine.