Fine-particle and single-phase microwave resonator materials such as l
anthanide titanates, Ln(2)Ti(2)O(7) (Ln = La, Nd and Sm), pyrochlore n
iobates, M(2)Nb(2)O(7) (M = Ca and Sr) and perovskite niobates, Ba(M(1
/3)Nb(2/3))O-3 (M = Mg and Zn) have been prepared by a combustion meth
od involving metal nitrates and tetraformal trisazine (TFTA) at 350 de
grees C. Particulate properties such as density, surface area and part
icle size and bulk properties such as density, microstructure and diel
ectric characteristics have been investigated.