Pr(BO2)3 und PrCl(BO2)2: Zwei meta-Borate des Praseodyms im Vergleich

Abstract

-009Pr(BO 2 ) 3 and PrCl(BO 2 ) 2 : Two Praseodymium meta-Borates in Comparison.-Single crystals of PrCl(BO 2 ) 2 (I) are obtained from the reaction of Pr 6 O 11 and PrCl 3 with excess B 2 O 3 (evacuated quartz tube, 850 • C, 7 d). The addition of NaCl as fluxing agent results in the formation of single crystals of Pr(BO 2 ) 3 (II) as the main product. (I) crystallizes in the triclinic space group P1 with Z = 2 and contains zigzag chains of corner-sharing BO 3 triangles. Pr 3+ is coordinated by three Cl − and seven O 2− anions forming a tetracapped trigonal prism. In the structure of compound (II) (monoclinic, space group C2/c, Z = 4) the boron atoms are present in both trigonal planar and tetrahedral oxygen coordination. The two types of polyhedra form chains via common corners. The coordination sphere of the Pr atoms is a bicapped square antiprism formed by ten O atoms.

Pr4B10O21: A new composition of rare-earth borates by high-pressure/high-temperature synthesis

“…The ions Pr1, Pr2, and Pr3 are coordinated by 10 oxygen atoms in the ranges 242-280, 241-278, and 231-301 pm, respectively (Table 3). Theses values fit well to the coordination polyhedra of the Pr 3+ ion in the praseodymium metaborate Pr(BO 2 ) 3 , where the Pr 3+ ions are also coordinated by 10 oxygen atoms with Pr-O distances ranging from 239 to 281 pm [32]. The fourth praseodymium ion (Pr4) in Pr 4 B 10 O 21 exhibits a larger CN of 12 with Pr-O distances of 243-314 pm.…”

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.…”

Ambient‐Pressure Stabilization of β‐GdB3O6 by Doping with Bi3+ and Color‐Tunable Emissions by Co‐Doping with Tb3+ and Eu3+: The First Photoluminescence Study of a High‐Pressure Polymorph

“…a-REB 3 O 6 (RE = La-Tb,e xcept Pm) was first reported in 1970 [7] and structurally characterized subsequently. [48][49][50][51] b-TbB 3 O 6 is the first member of the b-REB 3 O 6 (RE = Nd-Lu, except Pm) series. Although it was obtained under normalp ressure in am olten salt that contained Tb, Tb 4 O 7 ,T bCl 3 ,a nd B 2 O 3 at 950 8Cf or three weeks, [42] b-GdB 3 O 6 ,t he target compound of this work, was previously prepared at7 .5 GPa and 1050 8C.…”