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219,7JVg

-60 50 150 250 350

Temperature (fiC)

-60 50 150 250 350

Temperature (fiC)

Figure 54. Low-temperature DSC for [{P(Bun)3}2Cu(SEt)2In(SEt)2] (A) and [{P(Bun)3}2Cu(SPrn)2In(SPrn)2] (B). Reprinted with permission from [252], K. K. Banger et al., Thin Solid Films 403-404, 390 (2002). © 2002, Elsevier Science.

its use in the synthesis of microwave dielectric materials such as Ba(Mg1/3Nb2/3)O3 (BMN). Moreover, MgNb2O6 is the key material for the successful preparation of singlephase perovskite, Pb(Mg1/3Nb2/3)O3 (PMN), which is becoming increasingly important for multilayer ceramic capacitor, electrostrictor, and actuator applications [578, 579]. However, the synthesis of single-phase MgNb2O6 by solid-state methods is not straightforward, because of the formation of a corundum-like Mg4Nb2O9 phase [580], as observed in the XRD data for the powder calcined at high temperatures (Fig. 56). The transmission electron micrograph and selective area electron diffraction suggested the coexistence of orthorhombic MgNb2O6 and hexagonal Mg4Nb2O9 phases, which was confirmed by micro-EDX analysis of the grains (Fig. 56).

The use of metal organic precursors (S-diketonate derivatives of Pb and Mg and Nb(OR)5) also suffer from the problem of compatibility due to the differential hydrolysis rates of alkoxide and S-diketonate precursors [581]. Apotential solution to this problem is mixed-metal precursors like

Figure 55. Molecular structure of [{PPh3}2AgIn(SCOPh)4]. Reprinted with permission from [237], T. D. Devarajet al., Chem. Commun. 2304 (2001). © 2001, Royal Society of Chemistry.

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