The crystal structure of barium tetraborate, BaO.2B₂O₃

The crystal structure of kurnakovite: a refinement

“…The boron-oxygen coordinations are such as to make two tetrahedra (mean B-O distance 1.475 A) and one triangle (mean B-O distance 1.367 A), three oxygens being corner-shared in such a way as to build up a hexagonal ring [B303(OH)5] 2-. The same kind of B-O ring has been found in the dimorph inderite (Rumanova & Ashirov, 1963) and in the anhydrous analogue BaB407 (Block & Perloff, 1965), as pointed out by Clark (1971). Razmanova et al (1969) showed that the boroxol ring in kurnakovite deviates considerably from planarity if compared with that of inderite; this is confirmed in Table 6 which shows the displacements of the atoms in the anion from the plane containing the three oxygen atoms in the B303 ring; also, this plane makes an angle of 12 ° with that of the oxygen atoms in the triangular BOa group.…”

Raman scattering study of crystalline and melting states of BaO·2B2O3

“…Block and Perloff [3] found that barium tetraborate (a-BaO Á 2B 2 O 3 ) crystallizes in the monoclinic system, P2 1 /c. The melting point of a-BaO Á 2B 2 O 3 was 910 1C [3].…”

β-CaB4O7: A New Polymorph Synthesized under High-Pressure/High-Temperature Conditions

“…= 8), α-CaB 4 O 7 also transforms to the structure of its higher homologue SrB 4 O 7 [28,29]. The highest homologue in this series of tetraborates is monoclinic BaB 4 O 7 [62]. As BaB 4 O 7 exhibits BO 3 -next to BO 4 -units, it is improbable to represent a structure type Table 7.…”