Bi0.33Zr2(PO4)3, a negative thermal expansion material with a Nasicon-type structure

• Published in: Dalton transactions : an international journal of inorganic chemistry Vol. 51; no. 45; pp. 17310 - 17318
• Main Authors: Balaji, Daneshwaran, Kumar, Sathasivam Pratheep
• Format: Journal Article
• Language: English
• Published: Cambridge Royal Society of Chemistry 21.11.2022
• Subjects: Apexes; Diffraction patterns; Elongation; Extensometers; Sodium zirconium phosphate; Tetrahedra; Thermal expansion
• ISSN: 1477-9226; 1477-9234
• DOI: 10.1039/d2dt02914f

A new negative thermal expansion ceramic material, Bi0.33Zr2(PO4)3, with a sodium zirconium phosphate structure, has been investigated and the results are presented. A three-dimensional structural framework is formed by the interconnection of ZrO6 octahedra and PO4 tetrahedra through their vertices. The occupation of a Bi ion in a type I site, located between two ZrO6 octahedra along ZrO6 < PO4 > ZrO6 ribbons induced the structure to crystallize in a trigonal system with a P3c1 space group. The average thermal expansion coefficients between 300 and 1073 K are found to be αa = −12.99 × 10−6 K−1, αc = −26.67 × 10−6 K−1, and αv = −52.25 × 10−6 K−1. The large negative thermal expansion is highly associated with the peak shift towards a higher angle in temperature variable X-ray diffraction patterns, coupled rotation and distortion of ZrO6 octahedra and PO4 tetrahedra, and elongation or shrinkage in the Zr–O–P bond angles. Dilatometer results authenticate the negative thermal expansion behavior. The average bulk thermal expansion is registered as −0.73 × 10−6 K−1.