Powder diffraction crystal structure analysis using derivative difference minimization: example of the potassium salt of 1-(tetrazol-5-yl)-2-nitroguanidine

• Published in: Acta crystallographica. Section B, Structural science Vol. 61; no. 4; pp. 435 - 442
• Main Authors: Astachov, A. M., Molokeev, M. S., Vasiliev, A. D., Solovyov, Leonid A.
• Format: Journal Article
• Language: English; Russian
• Published: 5 Abbey Square, Chester, Cheshire CH1 2HU, England Munksgaard International Publishers 01.08.2005; Blackwell; Blackwell Publishing Ltd
• Subjects: Chemical compounds; Crystal structure; crystal structure analysis; derivative difference minimization; Diffraction; Potassium; powder diffraction; X-rays
• ISSN: 0108-7681; 2052-5192; 1600-5740; 2052-5206
• DOI: 10.1107/S0108768105015004

The crystal structure of the potassium salt of 1‐(tetrazol‐5‐yl)‐2‐nitroguanidine [K(C2H3N8O2)] was solved and refined from X‐ray powder diffraction data by applying the derivative difference minimization (DDM) method. The compound is of interest as an energetic substance. The structure model was found from a Patterson search. The reflection intensities for the Patterson synthesis were derived from the powder profile by applying a newly developed DDM‐based profile decomposition procedure. The use of the DDM method allowed successful location and unconstrained refinement of all the atomic positions, including those of three independent H atoms. The advantages of DDM in terms of the precision and reproducibility of the structural parameters are discussed in comparison to Rietveld refinement results. The failure to refine the H‐atom positions by the Rietveld method was attributed to systematic errors associated with the background modelling, which are avoided by DDM.