High-pressure X-ray diffraction studies of potassium chlorate

Journal Article · Thu Mar 15 04:00:00 EDT 2012 · J. Appl. Crystallogr.

DOI:https://doi.org/10.1107/S0021889811053957· OSTI ID:1033783

Pravica, Michael; Bai, Ligang; Bhattacharya, Neelanjan ^[1]

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1. UNLV

Two static high-pressure X-ray diffraction (XRD) studies of potassium chlorate have been performed at pressures of up to {approx}14.3 GPa in a diamond anvil cell at ambient temperature using the 16 ID-B undulator beamline at the Advanced Photon Source for the X-ray source. The first experiment was conducted to ascertain decomposition rates of potassium chlorate as a function of pressure. Below 2 GPa, the sample was observed to decompose rapidly in the presence of the X-ray beam and release oxygen. Above 2 GPa (near the phase I phase II transition), the decomposition rate dramatically slowed so that good quality XRD patterns could be acquired. This suggests a phase-dependent decomposition rate. In the second study, X-ray diffraction spectra were collected at pressures from 2 to 14.3 GPa by aligning virgin portions of the sample into the focused X-ray beam at each pressure. The results suggest the co-existence of mixed monoclinic (I) and rhombohedral (II) phases of potassium chlorate near 2 GPa. At pressures beyond 4 GPa, the XRD patterns show a very good fit to KClO{sub 3} in the rhombohedral phase with space group R3m, in agreement with earlier studies. No further phase transitions were observed with pressure. Decompression of the sample to ambient pressure indicated mixed phases I and II coupled with a small amount of synchrotron X-ray-induced decomposition product. The equation of state within this pressure regime has been determined.

• Research Organization: Advanced Photon Source (APS), Argonne National Laboratory (ANL), Argonne, IL (US)
• Sponsoring Organization: OTHERU.S. ARMY RESEARCH
• OSTI ID: 1033783
• Journal Information: J. Appl. Crystallogr., Journal Name: J. Appl. Crystallogr. Journal Issue: (1) ; 02, 2012 Vol. 45; ISSN 0021-8898; ISSN JACGAR
• Country of Publication: United States
• Language: ENGLISH

Related Subjects

43 PARTICLE ACCELERATORS
ADVANCED PHOTON SOURCE
AMBIENT TEMPERATURE
CHLORATES
DIAMONDS
OXYGEN
POTASSIUM
SPACE GROUPS
SPECTRA
SYNCHROTRONS
WIGGLER MAGNETS
X-RAY DIFFRACTION
X-RAY SOURCES