Hydrothermal synthesis and structural investigation of a new polymorph form of ndbo3

Abstract

The present work deals with the hydrothermal synthesis of a new polymorph form of neodymium orthoborate, NdBO3. It was obtained by dissolving 0.1875g B2O3 in 20 ml distilled water and later added to 1.8125 g Nd2O3 and the mixture was transferred to a teflon autoclave. The hydeothermal reaction was performed at 230 degrees C for 72 h. Characterizations of the sample were carried out by using X-Ray Powder Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR) and Thermal Analysis (DTA/TG) techniques. NdBO3 was crystallized in monoclinic system and unit cell parameters were calculated as a=11.726(1) angstrom, b=6.759(2) angstrom, c=9.909(4) angstrom, beta=114.50(0)degrees, and space group of C2/c. It was confirmed that NdBO3 was isostructural with the form of Er doped YBO3 (a=11.3138(3) angstrom, b=6.5403(2) angstrom, c=9.5499(2) angstrom and beta=112.902(1)degrees) at room temperature. The other significant invention of NdBo(3) was thermally stable up to 700 degrees C, but if the specimen was heated at 780 degrees C for 4 h, the monoclinic crystal structure was transformed to the aragonite form of NdBO3 (ICDD 12-756).