TY - JOUR
T1 - Decomposition of W(CO) 6 at high pressures and temperatures
AU - Rademacher, Nadine
AU - Bayarjargal, Lkhamsuren
AU - Friedrich, Alexandra
AU - Morgenroth, Wolfgang
AU - Avalos-Borja, Miguel
AU - Vogel, Sven C.
AU - Proffen, Thomas
AU - Winkler, Björn
PY - 2011/8
Y1 - 2011/8
N2 - The decomposition of hexacarbonyltungsten, W(CO) 6, has been studied. The decomposition was induced by heating W(CO) 6 in an autoclave at 523 K and pressures up to 1.8 MPa, and by laser heating in a diamond anvil cell at pressures between 5 and 18 GPa. The products have been characterized using synchrotron X-ray diffraction, pair distribution function analysis, Raman spectroscopy and scanning electron microscopy. Decomposition in the autoclave at the lower pressures resulted in the formation of a metastable tungsten carbide, W 2C, with an average particle size of 1-2 nm, and an unidentified nanocrystalline tungsten oxide and nanocrystalline graphite with average particle sizes of 1-2 and 11 nm, respectively. The existence of nanocrystalline graphite was deduced from micro-Raman spectra and the graphite particle size was extracted from the intensities of the Raman modes. The high-pressure decomposition products obtained in the diamond anvil cell are the monoclinic tungsten oxide phase WO 2 and the high-pressure phase W 3O 8(I). The approximate average size of the graphite particles formed here was 6-8 nm. The bulk modulus of W(CO) 6 is B 0 ≈ 13 GPa.
AB - The decomposition of hexacarbonyltungsten, W(CO) 6, has been studied. The decomposition was induced by heating W(CO) 6 in an autoclave at 523 K and pressures up to 1.8 MPa, and by laser heating in a diamond anvil cell at pressures between 5 and 18 GPa. The products have been characterized using synchrotron X-ray diffraction, pair distribution function analysis, Raman spectroscopy and scanning electron microscopy. Decomposition in the autoclave at the lower pressures resulted in the formation of a metastable tungsten carbide, W 2C, with an average particle size of 1-2 nm, and an unidentified nanocrystalline tungsten oxide and nanocrystalline graphite with average particle sizes of 1-2 and 11 nm, respectively. The existence of nanocrystalline graphite was deduced from micro-Raman spectra and the graphite particle size was extracted from the intensities of the Raman modes. The high-pressure decomposition products obtained in the diamond anvil cell are the monoclinic tungsten oxide phase WO 2 and the high-pressure phase W 3O 8(I). The approximate average size of the graphite particles formed here was 6-8 nm. The bulk modulus of W(CO) 6 is B 0 ≈ 13 GPa.
KW - Decomposition
KW - Raman spectroscopy
KW - X-ray diffraction
KW - pair distribution function
KW - scanning electron microscopy
UR - http://www.scopus.com/inward/record.url?scp=79960642619&partnerID=8YFLogxK
U2 - 10.1107/S0021889811021285
DO - 10.1107/S0021889811021285
M3 - Article
AN - SCOPUS:79960642619
SN - 0021-8898
VL - 44
SP - 820
EP - 830
JO - Journal of Applied Crystallography
JF - Journal of Applied Crystallography
IS - 4
ER -