10112-94-4Relevant articles and documents
Polymorphism of H2SeO3, NaHSeO4 and Na5H3(SeO4)4(H2O) 2, and re-refinement of the crystal structure of Te2O 4(OH)2
Pollitt, Stephan,Weil, Matthias
, p. 1622 - 1631 (2014/08/05)
New modifications (denoted as β-) of the compounds H 2SeO3, NaHSeO4, and Na5H 3(SeO4)4(H2O)2 were isolated from aqueous solutions and their crystal structures determined from single crystal data. β-H2SeO3 crystallizes in the space group P1 with lattice parameters of a = 4.6794(4) A, b = 5.0988(4) A, c = 5.7743(5) A, α = 102.252(6)°, β = 91.594(6)°, γ = 98.054(6)°, and consists of two unique trigonal-pyramidal SeO(OH)2 units that are held together by O-H...O hydrogen bonds. β-NaHSeO4 crystallizes in the space group P1 with lattice parameters of a = 5.0814(2) A, b = 5.6345(3) A, c = 6.5125(3) A, α = 88.352(3)°, β = 73.163(3)°, γ = 82.027(3)°, and is made up of distorted NaO 6 octahedra and tetrahedral SeO3(OH)- anions, with the hydrogen atom statistically disordered between two positions. β-Na5H3(SeO4)4(H 2O)2 crystallizes in the space group I2/c with lattice parameters of a = 7.0472(15) A, b = 13.194(3) A, c = 17.845(4) A, β = 101.345(9)°. The asymmetric unit contains three Na + sites (one situated on a twofold rotation axis and each with a distorted octahedral coordination by oxygen atoms), one water molecule, one SeO3(OH)- anion, and half of an [SeO 4...H...O4Se] unit with a very short interpolyhedral O...O distance of 2.447 (4) A. The crystal structures of the β-modifications are comparatively discussed with those of the corresponding known α-modifications. Moreover, the crystal structure of Te2O4(OH)2 was reinvestigated [Pna2 1, a = 12.0512(8) A, b = 8.0267(5) A, c = 4.7268(3) A], allowing the localization of the hydrogen atoms and hence a more detailed view of the hydrogen bonding system. Copyright
