Outline

In this project, Kyoto University (Japan) will establish an international exchange base with four universities and research institutes in the UK, France, Belgium, and China, and promote joint research on hydrides and fluorides, which have been recognized for their outstanding achievements in applications as functional materials. We will also establish a new network with other regions in Europe, America, Asia and Oceania.

1. Joint research

In the development of mixed anion compounds, it is essential to carry out research while organically coordinating synthesis, structural analysis, property measurement, and theoretical calculation. In order to promote this research project in close cooperation with other countries, the Japanese team consists of carefully selected members, mainly researchers who are active in the “mixed-anion” innovative area project and CREST.

Oxford (UK; science, physical chemistry) is responsible for the topochemical synthesis of materials such as hydrides and the development of physical functions such as superconductivity. By collaborating with the neutron scattering and synchrotron radiation facilities adjacent to Oxford and the world’s leading electron microscopy facility (EMAT Center) at the University of Antwerp (Belgium), it will be possible to solve structural problems unique to mixed anions that have been difficult to solve in the past.

Theoretical calculations based on molecular orbitals are essential for understanding and predicting mixed- anion systems. Theory will be studied at the Hoffmann Institute established in China in 2018 and named after Nobel laureate Roald Hoffmann. In addition, the University of Bordeaux (France) will be taking on the challenge of developing fluorides along with Kyoto University, with which they have had a longstanding relationship. The researchers on the Japanese side consist of experts in various techniques (high-pressure synthesis) and chemical functions such as (photo)catalysts and batteries, making it possible to conduct dynamic research between the five countries.

2. Seminars

In this project, workshops (oral and poster presentations) will be held once a year in Oxford, Kyoto, Antwerp, Tokyo, and Bordeaux where senior and mid-career researchers, young researchers, and students will gather to present the latest research results and progress on “mixed-anion” science. At the same time, senior and mid-career researchers will conduct lecture/seminar tours to several universities and research institutes to introduce cutting edge of mixed-anions approaches, build new networks, and connect to generate new research seeds. In the second and fourth years of the project, a school for young researchers will be held, where senior researchers will give lectures on “mixed-anion” science to young researchers and students to foster researchers who will lead the next generation.

3. Research Exchanges

Researchers at each center are indispensable for carrying out mixed anion research. Since they possess unique facilities, technologies, and experiences, exchanges and connection can break down the barriers between the fields and lead to a great leap forward in research and future industrial applications. Short- and long-term exchange programs for young researchers and students are important for accelerating collaboration. This not only allows young researchers to acquire new specialized knowledge and skills, but also allows them to plan and conduct research with free ideas, and to form a network of young researchers by themselves.

Through these efforts, we will establish a broad international community for mixed anionic materials and foster young researchers who will become the next generation of mixed anionic leaders. This active and flexible exchange among young researchers is expected to bring about novel methods and unexpected discoveries (serendipity).

4. Results

Many breakthrough have been obtained through the activities of the two projects: “Synthesis of Mixed Anion Compounds toward Novel Functionalities” (Grant-in-Aid for Scientific Research on Innovative Areas) and “new functions and inorganic materials based on anionic nanospaces” (CREST). In this program, we will organically collaborate with researchers at four partner institutions in the United Kingdom, France, Belgium, and China to develop new syntheses and synthetic methods for mixed anion compounds, develop and establish analytical techniques for mixed anion compounds, and discover innovative chemical and physical functions unique to anions. By developing and establishing analytical techniques for mixed anionic compounds and discovering innovative chemical and physical functions of anions, we will open up the frontier of inorganic materials.

Most mixed anion compounds are artificial compounds produced under controlled conditions, and are completely different from single anion systems such as oxides, which are often found in minerals in nature.  Mixed anion chemistry is not an extension of conventional crystallography and ceramic science, which have been developed on the basis of mineralogy, there are many unexplored areas and basic theories have not yet been established. This means that there is a high possibility of discovering completely new phenomena through the study of mixed anion compounds.

By establishing the basic theories of mixed anion compounds in this research, we can also establish design concepts and methodologies for materials that will lead to future practical applications.

From the viewpoint of material synthesis and analysis, we are aiming to realize “material design of mixed anion compounds,” “complete control of anion composition and coordination (order/disorder, cis-trans, etc.),” which has not yet been achieved in the long history of inorganic synthetic chemistry, and “development of new materials using interdisciplinary methods such as fusion of various synthetic methods. We also aim to establish “new synthetic methods that make full use of interdisciplinary techniques”.

In addition to the “oxyhydrides,” “fluorohydrides,” and “extended mixed anion systems” that we will concentrate on in this program, we can expect to synthesize a series of unique substances that do not fit into the category of conventional material systems or crystal structures. Mixed anion compounds are characterized by unique metal-anion coordination structures that are not found in single anion compounds such as oxides, and this has the potential to create functions that exceed those of perovskite oxides, also  known as treasure troves of functions.

As an outlet for the new functions and properties created by the unique coordination environment of mixed anions, we are working on the development of innovative chemical functionality in the fields of (photo)catalysis and batteries, innovative physical functionality such as novel topological phenomena, giant dielectricity, high-temperature superconductivity, and colossal magnetoresistance. We aim at developing multi-functional and emergent functional materials that combine the functions of different anion blocks.