Crystal Structures and Magnetic Properties of Rare-Earth Ultraphosphates, RP5O14 (R=La, Nd, Sm, Eu, Gd)

• Published in: Journal of solid state chemistry Vol. 150; no. 2; pp. 377 - 382
• Main Authors: Cole, J.M., Lees, M.R., Howard, J.A.K., Newport, R.J., Saunders, G.A., Schönherr, E.
• Format: Journal Article
• Language: English
• Published: San Diego, CA Elsevier Inc 01.03.2000; Elsevier
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Exact sciences and technology; Inorganic compounds; Magnetic properties and materials; Magnetically ordered materials: other intrinsic properties; Paramagnetic; Physics; RP5O14 structure; Salts; Saturation moments and magnetic susceptibilities; single-crystal X-ray diffraction; Structure of solids and liquids; crystallography; Structure of specific crystalline solids; single-crystal X-ray diffraction; RP5O14 structure; Paramagnetic; Temperature dependence; Inorganic compounds; Magnetization; Paramagnetism; Gadolinium Polyphosphates; XRD; Rare earth compounds; Experimental study; Magnetic susceptibility; Samarium Polyphosphates; Lanthanum Polyphosphates; Europium Polyphosphates; Neodymium Polyphosphates; Crystal structure
• ISSN: 0022-4596; 1095-726X
• DOI: 10.1006/jssc.1999.8610

The single-crystal X-ray structures of lanthanum, europium, and gadolinium ultraphosphate, RP5O14 (R=rare-earth) are reported herein [monoclinic, P21/c, a=8.8206(1), 8.7491(1), 8.7493(1) Å, b=9.1196(2), 8.9327(1), 8.9189(1) Å, c= 13.1714(2), 12.9768(2), 12.9717(1) Å, β=90.661(1), 90.534(1), 90.6682(3)°, respectively; Z=4; R1=0.0250, 0.0346, 0.0270, respectively]. The structures are all type (I) compounds as classified by Bagieu-Beucher and Tranqui [Bull. Soc. Fr. Miner. Cryst. 93, 505 (1970)]. The minimum R…R separations are compared with all other structural reports of lanthanide ultraphosphates. Type (I) compounds have the lowest minimum R…R separation, which decreases with atomic number and appears not to perturb the optical properties of any rare-earth ultraphosphate. In each case, R is surrounded exclusively by eight oxygen atoms that form a distorted square antiprism. A P–O network holds together the three-dimensional structure. The magnetic susceptibilities of neodymium, samarium, and gadolinium ultraphosphate as a function of temperature are also reported along with corresponding magnetization measurements. All compounds exhibit a paramagnetic response, following Curie's law except in the regions where crystal field splittings are significant.