Synthesis and structural properties of clinopyroxenes of the hedenbergite CaFe2+Si2O6 - aegirine NaFe3+Si2O6 solid-solution series

Characterization of synthetic hedenbergite (CaFeSi 2 O 6 )?petedunnite (CaZnSi 2 O 6 ) solid solution series by X-ray powder diffraction and 57 Fe M�ssbauer spectroscopy

“…1a. Values of the unitcell parameters for pure hedenbergite are similar to data found for an Fe 3+ -free sample characterized by Redhammer et al (2000). The unit-cell parameters of pure petedunnite corresponds with values reported for synthetic CaZnSi 2 O 6 by Essene and Peacor (1987), although they report large errors in their value (Table 3).…”

“…on an octahedral site. Similar parameters were reported for hedenbergite by Redhammer et al (2000), who synthesized samples at lower oxygen fugacities using magnetite-wuestite and iron-quartz-fayalite buffers, as shown in Figs. 6 and 7.…”

“…Crystal sizes up to 70 lm of intermediate members can be suitable for standard singlecrystal X-ray analysis (Heuer et al 2002a,b). In turn, tiny crystal sizes < 8 lm were observed in synthesis products of hedenbergite composition using gel (Nolan 1969;Kinrade et al 1975;Kawasaki and Ito 1994;Redhammer et al 2000) or ferrobustamite (Moecher and Chou 1990) as initial material. X-ray diffraction, Mo¨ssbauer spectra and microprobe analysis demonstrate that all members of the hedenbergite-petedunnite solid solution are well crystallized.…”

“…8. After 180 h curing time, clinopyroxenes of various compositions and synthesis conditions exhibit a minimum line width of 0.26 mm s )1 , considerably smaller than that of pure hedenbergite (G ¼ 0.32 mm s )1 ), synthesized from gels for 1369 h (Redhammer et al 2000). Kinrade et al (1975) studied the crystallization kinetics of hedenbergite from gels by means of Mo¨ssbauer spectroscopy.…”

“…The structures of end members hedenbergite and petedunnite were refined by Clark et al (1969) and Ohashi et al (1996), respectively. Hydrothermal synthesis of hedenbergite was performed by Nolan (1969), Rutstein and Yund (1969), Turnock et al (1973), Gustafson (1974), Kinrade et al (1975), Burton et al (1982), Haselton et al (1987), Moecher and Chou (1990), Raudsepp et al (1990), Perkins and Vielzeuf (1992), Kawasaki and Ito (1994), Zhang et al (1997) and Redhammer et al (2000). The stability of hedenbergite at 0.2 GPa as a function of temperature and oxygen fugacity was determined by Gustafson (1974) and Burton et al (1982).…”