Crystal Structure of Lanthanum Bismuth Silicate Bi2-xLaxSiO5 (x≈0.1).
Crystal Structure of Lanthanum Bismuth Silicate Bi2-xLaxSiO5 (x≈0.1).
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DOI：
10.1002/chin.200713005
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发表时间：
2007-03
期刊：
影响因子：
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通讯作者：
S. Georges;F. Goutenoire;P. Lacorre
中科院分区：
文献类型：
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作者：
S. Georges;F. Goutenoire;P. Lacorre
A melting and glass recrystallization route was carried out to stabilize a new tetragonal form of Bi2SiO5with bismuth partially substituted by lanthanum. The crystal structure of Bi2−xLaxSiO5(x∼0.1) was determined from powder X-ray and neutron diffraction data (space group I4/mmm, a=b=3.8307(3)Å, c=15.227(1)Å, V=224.18Å3, Z=2; reliability factors: RBragg=5.65%, Rp=14.6%, Rwp=16.8%, Rexp=8.3%, χ2=8.3 (X-ray) and RBragg=2.40%, Rp=8.1%, Rwp=7.5%, Rexp=4.2%, χ2=3.3 (neutrons); 11 structural parameters refined). The main effect of lanthanum substitution is to introduce, by removing randomly some bismuth 6s2lone pairs, a structural disorder in the surroundings of (Bi2O2)2+layers, that is in the (SiO3)2−pyroxene files arrangement. It results in a symmetry increase relatively to the parent compound Bi2SiO5, which is orthorhombic. The two structures are compared.
