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X‐ray Diffraction Study on MgSeO 4 . 6 H 2 O at Elevated Temperatures
Author(s) -
Stoilova D.,
Koleva V.
Publication year - 1995
Publication title -
crystal research and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.377
H-Index - 64
eISSN - 1521-4079
pISSN - 0232-1300
DOI - 10.1002/crat.2170300421
Subject(s) - triclinic crystal system , orthorhombic crystal system , monoclinic crystal system , crystallography , anhydrous , selenate , lattice constant , crystal structure , hydrate , x ray crystallography , amorphous solid , powder diffraction , chemistry , magnesium , diffraction , materials science , selenium , physics , organic chemistry , optics
The dehydration of MgSeO 4 . 6 H 2 O has been studied using an X‐ray powder diffraction method at elevated temperatures. Five different solid phases have been identified in the temperature interval of 20–450 °C: MgSeO 4 . 6 H 2 O; MgSeO 4 . 5 H 2 O (with a small amount of MgSeO 4 . 4 H 2 O), MgSeO 4 . 2 H 2 O, amorphous MgSeO 4 and crystalline MgSeO 4 . MgSeO 4 . 5 H 2 O crystallizes in the triclinic system with the lattice parameters: a = 6.403(2) Å, b = 10.576(5) Å, c = 6.196(3) Å, α = 98.63(2)°, β = 110.36(2)°, γ = 75.25(3)°, SG P 1 . MgSeO 4 . 2 H 2 O forms orthorhombic crystals with lattice parameters: a = 10.304(1) Å, b = 10.351(9) Å, c = 9.138(9) Å. The crystalline anhydrous magnesium selenate crystallizes in the orthorhombic system with the lattice parameters: a = 4.925(2) Å, b = 9.026(5) Å, c = 6.816(6) Å. Additionally MgSeO 4 . 4 H 2 O has been prepared and studied roentgenographically: monoclinic system with the lattice constants: a = 6.064(4) Å, b = 13.773(7) Å, c = 8.062(6) Å, β = 91.82(7)°, SG P2 1 /n. According to expectation the magnesium selenate hydrates are isomorphous with the corresponding magnesium sulphate hydrates.