Synthesis and Characterization of the New Strontium Borogermanate Sr_3–x/2B_2–xGe_4+xO₁₄ (x = 0.32)

Abstract

The strontium borogermanate Sr(3-x/2)B(2-x)Ge(4+x)O14 (x = 0.32) was synthesized by high-temperature solid-state reaction of SrO, GeO2, and H3BO3 in a NaF/KF flux system using platinum crucibles. The structure determination revealed that Sr(3-x/2)B(2-x)Ge(4+x)O14 (x = 0.32) crystallizes in the trigonal space group P321 (No. 150) with the parameters a = 800.7(2) and c = 488.8(2) pm, with R1 = 0.0281, wR2 = 0.0671 (all data), and Z = 1. The crystal structure of Sr(3-x/2)B(2-x)Ge(4+x)O14 (x = 0.32) consists of distorted SrO8 cubes, GeO6 octahedra, GeO4 tetrahedra, and BO4 tetrahedra. In addition to the structural investigations, Raman and IR spectroscopic investigations were carried out.

Ba4Bi2(Si8−xB4+xO29) (x = 0.09): a new acentric metal borosilicate as a promising nonlinear optical material

“…It exhibits an SHG response of 5.1 × KDP. In this compound, mixing of B atoms and Si atoms for some atomic sites occurred, which is similar to what was observed for a few borogermanates previously reported 30,31. In this work, the synthesis, crystal structure, second-order nonlinear-optical effects, and thermal stability of this compound are reported.…”

“…The mixed Ge 4+ /B 3+ site is tetrahedrally coordinated with Ge 4+ (16%) and B 3+ (84%). The B/GeO 4 tetrahedron connects with three other GeO 4 tetrahedra by sharing three corners in a layered structure 31. We deem that the mixing of B and Si atoms at the same site should be more likely compared with the B/Ge mixing due to being closer in size; hence we believe that more similar examples will be found in the future.…”

“…About the site-mixing of B and Si atoms, it is not very common in the borosilicates reported. However two borogermanates, namely, CsB x Ge 6– x O 12 ( x = 1) (CBGO) and Sr 3– x /2 B 2– x Ge 4+ x O 14 ( x = 0.32) (SBGO), have been reported to exhibit the mixing of the B and Ge atoms at the same site 30,31. There is only one mixed occupied site of B 3+ /Ge 4+ in the structure of CBGO, and it has the percentage of B 3+ (16.6%) and Ge 4+ (83.3%).…”

“…Considering the coordination environment of beryllium atoms, a very effective strategy is to replace BeO 4 tetrahedra with PO 4 , SiO 4 and GeO 4 , which led to the formation of a variety of metal borophosphates, borogermanates and borosilicates, including Ba 3 (ZnB 5 O 10 )PO 4 , Na 4 MB 2 P 3 O 13 (M = Rb, Cs), A 2 EB 4 O 9 (A = Cs, Rb) (E = Si, Ge), AEB 3 O 7 (A = Cs, Rb) (E = Si, Ge), and Ba 4 (BO 3 ) 3 (SiO 4 )·Ba 3 X (X = Cl, Br) 22–29. Recently, the partial disorder between Ge atoms and B atoms in tetrahedral positions has led to borogermanates with interesting structures, as shown by CsB x Ge 6– x O 12 ( x = 1) and Sr 3– x /2 B 2– x Ge 4+ x O 14 ( x = 0.32) 30,31…”

Synthesis and characterization of PbBaGeO4

“…The single crystal structure determination of the latter phase revealed that the compound crystallizes isotypically to BaNdGaO 4 [4] being related to the β-K 2 SO 4 [5,6] structure type. Interestingly, a variation of the flux material into the system NaF/KF led to the successful synthesis of the new strontium borogermanate Sr 3 − x/2 B 2 − x Ge 4 + x O 14 (x = 0.32) [7]. The synthesis of PbSrGeO 4 aroused our interest to expand the group of lead alkaline earth metal germanates by substituting strontium for barium.…”