New Phosphate-Sulfates with NZP Structure

• Published in: Russian journal of inorganic chemistry 2018-06, Vol.63 (6), p.714-724
• Main Authors: Savinykh, D. O., Khainakov, S. A., Orlova, A. I., Garcia-Granda, S.
• Format: Article
• Language: English
• Subjects: Anisotropy; Chemistry; Chemistry and Materials Science; Copper; Crystal structure; Inorganic Chemistry; Iron; Magnesium; Nickel; Sodium zirconium phosphate; Sol-gel processes; Solid solutions; Sulfates; Synthesis and Properties of Inorganic Compounds; Thermal expansion; Thermal stability; Zinc
• ISSN: 0036-0236; 1531-8613
• DOI: 10.1134/S0036023618060207

NaZr 2– x B x (PO 4 ) 3–2 x (SO 4 ) 2 x (0 ≤ x ≤ 1.25, B = Mg, Co, Ni, Cu, Zn), and NaZr 2– x R x (PO 4 ) 3– x (SO 4 ) x (0 ≤ x ≤ 1.25, R = Al, Fe) phosphate-sulfates series have been prepared by a sol–gel process. These compounds belong to the NaZr 2 (PO 4 ) 3 (NZP) structure family and crystallize in hexagonal crystal system, space group R 3 ¯ c . Limited solid solution series were found to exist; their formation temperatures and thermal stability limits were determined. Particle sizes as determined by microstructure observation were 50–200 nm, and for Cu- and Zn-containing samples, 200–500 nm. The thermal expansion of phosphate-sulfate NaZr 1.25 Cu 0.75 (PO 4 ) 1.5 (SO 4 ) 1.5 was studied in the range 25–700°C. Thermal expansion coefficients and thermal expansion anisotropy were found to be α a =–5.40 × 10 –6 °C –1 , α с = 18.88 × 10 –6 °C –1 , α avg = 2.69 × 10 –6 °C –1 , and Δα = 24.28 × 10 –6 °C –1 .