Synthesis of tin(IV) nitride with spinel structure, γ -Sn ₃ N ₄ , from the elements and its Raman-spectroscopic examination at high pressures

Abstract

We report on the synthesis of tin(IV) nitride with spinel structure, γ -Sn 3 N 4 , from the elements at high pressures and temperatures using a laser-heated diamond anvil cell, and on the Rietveld refinement of the product structure. The procedure described here is, in our opinion, the most reliable method of obtaining high-purity nitrides which are thermodynamically stable only at high pressures. Raman spectroscopy and powder X-ray diffraction were used to characterize the synthesis products. Pressure dependences of the Raman-band frequencies of γ -Sn 3 N 4 were measured and used to determine its average mode Grüneisen parameter, 〈 γ 〉 = 0.95. Using this value, we estimated the thermal-shock resistance of γ -Sn 3 N 4 to be about half that of γ -Si 3 N 4 , which, in turn, is moderately surpassed by β -Si 3 N 4 , known to be highly thermal-shock resistant. This article is part of the theme issue ‘Exploring the length scales, timescales and chemistry of challenging materials (Part 1)’.

Exploring the length scales, timescales and chemistry of challenging materials (Part 1)

“…Spinel structures are also commonly encountered at high pressure, and Andreas Zerr presents a study of a tin nitride, synthesized in situ in a laser-heated diamond anvil cell [ 29 ]. The starting materials are elemental tin and molecular nitrogen, and the application of both high pressure and high temperature are shown to result in formation of the γ-Sn 3 N 4 spinel at 10–20 GPa and 2000°C.…”