Research output: Contribution to journal › Article › peer-review
Synthesis, crystal structure and thermal behavior of Rb3B7O12, a new compound. / Bubnova, R. S.; Polyakova, I. G.; Krivovichev, S. V.; Shakhverdova, I. P.; Filatov, S. K.; Krzhizhanovskaya, M. G.; Burns, P. C.
In: Solid State Sciences, Vol. 4, No. 7, 01.01.2002, p. 985-992.Research output: Contribution to journal › Article › peer-review
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TY - JOUR
T1 - Synthesis, crystal structure and thermal behavior of Rb3B7O12, a new compound
AU - Bubnova, R. S.
AU - Polyakova, I. G.
AU - Krivovichev, S. V.
AU - Shakhverdova, I. P.
AU - Filatov, S. K.
AU - Krzhizhanovskaya, M. G.
AU - Burns, P. C.
PY - 2002/1/1
Y1 - 2002/1/1
N2 - A new compound, Rb3B7O12, has been synthesized using solid state reaction and glass crystallization methods. It is triclinic, space group P-1, a = 6.603(1), b = 6.632(1), c= 30.085(6), Å, α = 91.183(4), β = 91.781(4), γ = 119.293(3)°, V = 1147.5(5) Å3, Z =4. The crystal structure of the compound has been solved by direct methods and refined to R1 = 0.068 (ωR = 0. 142) on the basis of 1840 unique observed reflections (|Fo| > 4σ |Fo|). The structure is based upon a novel [B7O12] layered anion. The layer is parallel to (0 0 1) and is composed of four types of rigid boron-oxygen groups: two [B5O8.5]2- pentaborate groups, [B3O5]- triborate groups and BO4 single tetrahedra. There are six symmetrically independent Rb atoms in the structure, of which four are located in voids within the borate layer and two are between the layers. High-temperature X-ray powder diffraction studies showed that the new compound forms above 620 °C as a result of the solid state reaction Rb2B4O7 + α-RbB3O5 ↔ Rb3B7O12. The compound melts at ∼ 700°C according to the peritectic reaction Rb3B7O12 ↔ βRbB3O5 + liquid. Thermal expansion of the structure of Rb3B7O12 is highly anisotropic (α11 = 34, α22 = 9, α33 = 2 × 10-6°C-1). The thermal expansion is maximal in the direction perpendicular to the plane of the layer (α11 = 34 × 10-6°C-1).
AB - A new compound, Rb3B7O12, has been synthesized using solid state reaction and glass crystallization methods. It is triclinic, space group P-1, a = 6.603(1), b = 6.632(1), c= 30.085(6), Å, α = 91.183(4), β = 91.781(4), γ = 119.293(3)°, V = 1147.5(5) Å3, Z =4. The crystal structure of the compound has been solved by direct methods and refined to R1 = 0.068 (ωR = 0. 142) on the basis of 1840 unique observed reflections (|Fo| > 4σ |Fo|). The structure is based upon a novel [B7O12] layered anion. The layer is parallel to (0 0 1) and is composed of four types of rigid boron-oxygen groups: two [B5O8.5]2- pentaborate groups, [B3O5]- triborate groups and BO4 single tetrahedra. There are six symmetrically independent Rb atoms in the structure, of which four are located in voids within the borate layer and two are between the layers. High-temperature X-ray powder diffraction studies showed that the new compound forms above 620 °C as a result of the solid state reaction Rb2B4O7 + α-RbB3O5 ↔ Rb3B7O12. The compound melts at ∼ 700°C according to the peritectic reaction Rb3B7O12 ↔ βRbB3O5 + liquid. Thermal expansion of the structure of Rb3B7O12 is highly anisotropic (α11 = 34, α22 = 9, α33 = 2 × 10-6°C-1). The thermal expansion is maximal in the direction perpendicular to the plane of the layer (α11 = 34 × 10-6°C-1).
UR - http://www.scopus.com/inward/record.url?scp=0036322255&partnerID=8YFLogxK
U2 - 10.1016/S1293-2558(02)01341-9
DO - 10.1016/S1293-2558(02)01341-9
M3 - Article
AN - SCOPUS:0036322255
VL - 4
SP - 985
EP - 992
JO - Solid State Sciences
JF - Solid State Sciences
SN - 1293-2558
IS - 7
ER -
ID: 47838763