Preface

A cation coordinated with the surrounding oxide ions to form an oxoate ionic group (M m O n ) p¹ chemically bonds to another cation N q+ as a(M m O n ) p¹ •bN q+ to comprise an oxoate ceramic.The constants of a, b, m, n and the valences of p and q are used as superficial symbols for convenience.Well-known oxoates are silicates, phosphates and sulfates-based compounds, and manganates, vanadates, tungstates, chromates, and molybdates also form oxoate ceramics.As shown below, the central atoms of M in an oxoates group (M m O n ) p¹ can form solid solutions with another oxoates as (M m M s O s ) p¹ , a novel compound can be produced by an effect of mixed oxoate ions.Another benefit is the use of multiple metal and transitional ions in addition to typical elements as N for the design of novel functional ceramics.To date, the functions and applications of oxoate ceramics stem from electronic ceramics such as cobaltates and manganates for battery electrodes, titanates and niobates as ferroelectrics to environmental reproducing devices of silicates and carbonates, and to biomedical phosphates as artificial bone and teeth.The study on oxoate ceramics is thus currently gathering an intensive attention for both purposeful design and controlled production of a novel functional ceramic.As mentioned above, the study on oxoate ceramics covers interdisciplinary fields of ceramic science and engineering.Under such circumstances, we, the members of the Oxoate Ceramics Research Association in the Ceramic Society of Japan, have proposed the publication of the special issue of "Current Development and Future Potentiality of Functional Oxoate Ceramics".