New phases in the binary system PbO–BiVO 4 : Pb 2 BiVO 6 and Pb 4 BiVO 8
1995; Royal Society of Chemistry; Volume: 5; Issue: 6 Linguagem: Inglês
10.1039/jm9950500901
ISSN1364-5501
AutoresAriane Mizrahi, Jean‐Pierre Wignacourt, M. Drache, P. Conflant,
Tópico(s)Luminescence Properties of Advanced Materials
ResumoThe binary system PbO–BiVO4 exhibits two new phases, Pb4BiVO8 and Pb2BiVO6. They both melt congruently at 780 °C. They have been identified by single-crystal and powder X-ray diffraction. Pb4BiVO8 crystallizes with a triclinic cell, a= 6.221(2)Å, b= 7.603(5)Å, c= 10.457(4)Å, α= 100.40(3)°, β= 102.18(2)°, γ= 90.03(3)° and Z= 2. Pb2BiVO6 exhibits four phase transitions at 300, 415, 475 and 600 °C. The α phase, room-temperature form, is monoclinic with a=7.642(6)Å, b= 5.81 2(5)Å, c= 28.85(2)Å, β=100.3(1)° and Z= 8. The β and γ phases are orthorhombic with a= 8.381(6)Å, b= 16.65(1)Å, c= 4.859(6)Å, Z= 4 and a=14.304(7)Å, b=10.14(1)Å, c= 9.923(4)Å, Z= 8, respectively. The δ phase is tetragonal with a= 12.110(2)Å, c= 9.472(8)Å and Z= 8.
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