Materials discovery and development necessarily begins with the preparation and identification of product phase(s). Crystalline compounds can be identified by their characteristic diffraction patterns using X-rays, neutrons, and or electrons. An estimated 20,000 X-ray diffractometers and a comparable number of electron microscopes are used daily in materials research and development laboratories for this purpose. Access to crystal structure data is a critical step in solving research and applications problems in materials researches, and these data are of interest to analysts in areas such as materials design, property prediction and compound identification. NIST Crystallographic Data Center, in collaboration with partners all over the world, evaluates and disseminates chemical, physical and crystallographic information published on these materials. NIST Standard Reference Database 3: NIST Inorganic Crystal Structure Database (NIST ICSD) is a comprehensive collection of crystal structure data of nonorganic compounds (including inorganics, ceramics, minerals, pure elements, metals, and intermetallic systems) containing over 210,000 entries and covering the literature from 1913. NIST ICSD includes entries that fall into the following categories: full structure data from experimental refinement or derived from their iso-structural structure types, theoretically predicted structures from computer simulations, as well as partially characterized structures. The NIST ICSD web application provides materials researchers with a user-friendly interface to search the database based on bibliographic information, chemistry, unit cell, space group, experimental settings, mineral name/group and other derived data from expert evaluation. In addition, it also provides users with functions to easily create and examine results from various crystallographic computations, such as reduced cell, bond distance/angle, calculated powder diffraction data, and structure standardization.

The Inorganic Crystal Structure Database (ICSD) is produced cooperatively by the Fachinformationszentrum Karlsruhe (FIZ) and the National Institute of Standards and Technology (NIST). Components and devices used in a broad spectrum of technology sectors such as health care, communications, energy and electronics are manufactured from crystalline materials; the development of advanced crystalline materials requires accurate crystal-structure data. SRD 84 ICSD provides critically evaluated, comprehensive crystal-structure data and search software that enable phase identification by their characteristic diffraction patterns using X-rays, neutrons and electrons. SRD 84 ICSD contains full crystallographic and atomic-position information for more than 180,000 non-organic materials, including inorganics, ceramics, minerals, pure elements, metals and intermetallics, published in literature from 1913 through the present. ICSD is updated twice a year, with each update comprising about 2,000 to 10,000 new or re-evaluated entries. Data items include bibliographic information, compound designation such as chemical name, chemical formula, mineral name; and crystallographic parameters such as unit cell, space group, element symbol with numbering, oxidation state, multiplicity for Wyckoff position, x,y,z coordinates, site occupation, thermal parameters and reliability index R, among others. A free demonstration CD which includes a comprehensive user interface, FindIt, for a demo database is available upon request or can be downloaded from the website https://www.nist.gov/srd/nist-standard-reference-database-84.

We propose a machine-learning method to recommend successful processing conditions for new compounds on the basis of parallel experiments. Initially, an experimental database was constructed for 67 pseudobinary oxides registered in the Inorganic Crystal Structure Database (ICSD) by parallel experiments using 23 starting materials and 23 cation mixing ratios. Precursor powders were obtained by four synthesis methods (solid-state reaction, polymerized complex, cyclic ether sol–gel, and spray coprecipitation), which were fired at five different temperatures. This resulted in 1648 unique chemical synthesis conditions and database entries. The reactants were characterized sequentially using powder X-ray diffraction equipment with an automatic sample exchanger. The synthesis results were rated as a score, which was placed into a fifth-order tensor with 243 340 elements. The Tucker decomposition method was used to predict yet-to-be-rated scores for unexperimented processing conditions. Good predictive performance of the present model was demonstrated by cross validation. It was further evaluated by examining the presence of highly rated compositions in another database, ICDD-PDF (International Center for Diffraction Data-Powder Diffraction File). Successful processing conditions for unexperimented compositions were found to be well recommended.

Figure 1: X-ray diffraction (XRD) patterns of Al–ZnO(15 min)/ZnO(t)/ITO/glass samples for t = 100 min, 60 min, 40 min. Inorganic Crystal Structure Database (ICSD) patterns are also shown (red columns for ZnO and blue columns for ITO) with the pdf-number 01-074-0534 36-1451 regarding ZnO.