TY - JOUR

T1 - A new borosilicate feldspar, KBSi3O8: Synthesis, crystal structure and thermal behavior

AU - Krzhizhanovskaya, M.G.

AU - Bubnova, R.S.

AU - Depmeier, W.

AU - Rahmoun, N.S.

AU - Filatov, S.K.

AU - Ugolkov, V.L.

PY - 2012

Y1 - 2012

N2 - Single crystals of the new borosilicate feldspar with nominal composition KBSi3O8 were grown hydrothermally. The crystal structure of KBSi3O8 was determined by direct methods: it is monoclinic, C2/m, a=8.4377(8), b=12.4152(11), c=6.8769(7) Å, β = 116.133(7)°, V = 646.75(11) Å3, dcalc = 2.693 g/cm3. The structure corresponds to that of monoclinic aluminosilicate feldspar with differences only in the size and density of the tetrahedral framework due to the presence of boron instead of aluminium. The distribution of Si and B over the tetrahedral sites is partially ordered with one Si-rich tetrahedron ( = 1.60 Å), and another one occupied by Si and B in almost equal proportion ( = 1.55 Å). According to the high temperature X-ray diffraction study the expansion of the structure is highly anisotropic: α1 = 21, α2 = 2, α3 = 5 × 10–6 K–1, ∠(α3c) = 7°. The direction of maximal expansion approximately coincides with the short diagonal of the ac parallelogram. KBSi3O8 obtained by hydrothermal synthesis is

AB - Single crystals of the new borosilicate feldspar with nominal composition KBSi3O8 were grown hydrothermally. The crystal structure of KBSi3O8 was determined by direct methods: it is monoclinic, C2/m, a=8.4377(8), b=12.4152(11), c=6.8769(7) Å, β = 116.133(7)°, V = 646.75(11) Å3, dcalc = 2.693 g/cm3. The structure corresponds to that of monoclinic aluminosilicate feldspar with differences only in the size and density of the tetrahedral framework due to the presence of boron instead of aluminium. The distribution of Si and B over the tetrahedral sites is partially ordered with one Si-rich tetrahedron ( = 1.60 Å), and another one occupied by Si and B in almost equal proportion ( = 1.55 Å). According to the high temperature X-ray diffraction study the expansion of the structure is highly anisotropic: α1 = 21, α2 = 2, α3 = 5 × 10–6 K–1, ∠(α3c) = 7°. The direction of maximal expansion approximately coincides with the short diagonal of the ac parallelogram. KBSi3O8 obtained by hydrothermal synthesis is

KW - Single crystal X-ray diffraction

KW - Hydrothermal synthesis

KW - Thermal expansion

KW - Feldspar

KW - Borosilicate

M3 - Article

VL - 227

SP - 446

EP - 451

JO - Zeitschfrift fur Kristallographie

JF - Zeitschfrift fur Kristallographie

SN - 0044-2968

IS - 7

ER -