Zur Kenntnis der Borate Seltener Erden. Die Verbindungen SE(BO₂)₃

Abstract

Die Verbindungen SE(BO2)3 wurden für SE  La, Ce, Pr, Nd, Sm, Eu, Gd und Tb dargestellt, röntgenographisch und mittels DTA untersucht. Sie sind monoklin und zeigen derart ähnliche Röntgenpulverdiagramme, daß Isotypie anzunehmen ist. Auf Grund der Untersuchungsdaten lassen sich die Reaktionen der Seltene Erden‐Oxide mit Bortrioxid in ein Schema einordnen.

High-Pressure Syntheses, Crystal Structures, And Thermal Behaviour Of β-Re(Bo2)3 (Re = Nd, Sm, Gd)

“…Up to now, four modifications of rare earth meta-borates are known, designated chronologically as α-, β -, γ-, and δ -RE(BO 2 ) 3 . The monoclinic phases α-RE(BO 2 ) 3 (RE = La [1,2], Ce [3], Pr [4], Nd [5,6], Sm [7], Eu [8], Gd [7], Tb [9]) crystallize in the space group I2/a. They are built up of chains of triangular [BO 3 ] 3− and tetrahedral [BO 4 ] 5− units, representing the longest known phases.…”

Growth, structure, and optical properties of a self-activated crystal: Na3Nd9O3(BO3)8

“…The major phase of sample before melting was found to be Na 3 Nd 9 O 3 (BO 3 ) 8 since it was in agreement with the calculated pattern based on the single crystal crystallographic data, and the trace phase was (15) lambda-NdBO 3 (JCPDS Card File 12e0756) [15] impurities. However, the major phase of sample after melting was lambda-NdBO 3 [15], and the minor phase was Nd(BO 2 ) 3 (JCPDS Card File 23e1260) [16]. The phases containing Na were not identified from diffraction patterns, which probably results from their trace content and high volatility.…”

Polymorphy of monoclinic terbium triborate, TbB3O6

“…With the structure determination of CeB 3 O 6 , PrB 3 O 6 and EuB 3 O 6 (and a redetermination of NdB 3 O 6 ) the isostructural series was complemented later [8][9][10][11]. For TbB 3 O 6 , that had been reported in the 1970's either with orthorhombic or with monoclinic cell parameters [12][13][14], crystals of both phases, orthorhombic and monoclinic TbB 3 O 6 , were synthesized and structurally characterized lately [15,16]. Supplementing the isomorphic series of REB 3 O 6 with RE = La -Gd, monoclinic TbB 3 O 6 crystallizes with space group I2/a (i.e.…”