T:Toxic;
7446-08-4Relevant articles and documents
Study of the system Pr2O3-SeO2-H2O at 100°C and the properties of the compounds obtained
Gospodinov,Stancheva
, p. 95 - 100 (2004)
The solubility of the system Pr2O3-SeO2-H2O at 100°C was studied. The fields of crystallization of Pr2(SeO3)3·H2O, PrH(SeO3)2, Pr(HSeO3/sub
Kinetics of isothermal decomposition of ZnSeO3 and CdSeO 3
Vlaev,Georgieva,Gospodinov
, p. 163 - 168 (2005)
The kinetics of decomposition of ZnSeO3 and CdSeO3 was studied under isothermal heating on a derivatograph. The values of activation energy, pre-exponential factor in Arrhenius equation and change of entropy were calculated for the formation of the activated complex by the reagent. The dependencies observed are interpreted according to the generalized perturbation theory of chemical reactivity.
The synthesis and crystal structures of the first rare-earth alkaline-earth selenite chlorides MNd10(SeO3)12Cl8 (M=Ca and Sr)
Berdonosov,Olenev,Dolgikh,Lightfoot
, p. 3019 - 3025 (2007)
Two new alkaline-earth Nd selenite chlorides MNd10(SeO3)12Cl8 (M=Ca, Sr) were obtained using crystal growth from alkaline-earth chloride melts in quartz tubes. These new compounds crystallize in the orthorhombic system in space group C cca (#68). The compounds were studied by energy dispersive X-ray spectroscopy (EDX) and X-ray diffraction. It was shown that both compounds adopt the same structure type, constructed by complex [M11(SeO3)12]8+ slabs separated by chloride anion layers perpendicular to the longest cell parameter. The SeO3 groups show a pyramidal shape and may be described as SeO3E tetrahedra. Such SeO3 groups decorate the Nd-O skeletons forming the [M11(SeO3)12]8+ slabs.
A study of the selenites of cerium phase states in aqueous medium and thermal properties
Gospodinov,Stancheva
, p. 859 - 865 (2003)
The solubilities of the systems CeO2-SeO2-H 2O and Ce2O3-SeO2-H2O were studied at 100°C. The field of crystallization of Ce(SeO 3)2 was established in the system CeO2-SeO 2-H2O, and fields of crystallization of Ce 2(SeO3)3 and Ce2(SeO 3)3 H2SeO3 were established in the system Ce2O3-SeO2-H2O. The compound obtained were identified by means of chemical, X-ray and derivatograph analysis. The mechanism of thermal dissociation of Ce(SeO3)2, Ce2(SeO3)3 and Ce2(SeO 3)3H2SeO3 was studied.
Structural and thermal studies on the solid products in the system MnSeO3-SeO2-H2O
Vlaev,Tavlieva, Mariana P.
, p. 385 - 392 (2007)
The solubility of MnSeO3-SeO2-H2O system was studied in the temperature region 25-300°C. The compounds of the three-component system were identified by the Schreinemaker's method. The phase diagram of manganese(II) selenit
Mild Hydrothermal Synthesis of Cu(SeO3).2H2O: Structural Characterization, Thermal, Spectroscopic and Magnetic Studies
Larranaga, Aitor,Mesa, Jose L.,Lezama, Luis,Arriortua, Maria I.,Rojo, Teofilo
, (2009)
Cu(SeO3).2H2O has been synthesized by hydrothermal technique under autogeneous pressure. The compound crystallizes in the P212121 orthorhombic space group. The unit cell parameters are a = 6.672(1), b
Cadmium copper selenite chloride, CdCu2(SeO3)2Cl2, an insulating spin gap system
Berdonosov, Peter S.,Danilovich, Igor L.,Dolgikh, Valery A.,Murtazoev, Alisher F.,Pchelkina, Zlata V.,Tafeenko, Victor A.,Vasiliev, Alexander N.
, (2021)
Novel copper cadmium selenite chloride has been synthesized via vapor transport reaction as well as by solid state process. CdCu2(SeO3)2Cl2 crystallizes in a monoclinic space group I2/a with cell constants a ?= ?7.8057(3) ?, b ?= ?9.6036(4) ?, c ?= ?10.7817(5) ? and β ?= ?102.362(4)°, Z ?= ?4. Its crystal structure can be described as an open channel three-dimensional framework, formed by [CdO2Cl4] and [CuO4Cl2] polyhedra interconnected by pyramidal SeO3 groups. The copper polyhedra form magnetically isolated dimers with a spin gap Δ ?= ?38.7 ?± ?0.8 ?meV, as defined from magnetic susceptibility measurements. The electron band gap estimated by diffuse reflectance method Eg ?= ?2.82 ?± ?0.02 ?eV is in agreement with the yellow-green color of the substance. Density functional theory provides the values of electron (2.4 ?eV) and spin (36.6 ?meV) gaps consistent with experimental observations.
Syntheses, structures, and properties of Ag4(Mo2O5)(SeO4)2(SeO3) and Ag2(MoO3)3SeO3
Ling, Jie,Albrecht-Schmitt, Thomas E.
, p. 1601 - 1607 (2007)
Ag4(Mo2O5)(SeO4)2(SeO3) has been synthesized by reacting AgNO3, MoO3, and selenic acid under mild hydrothermal conditions. The structure of this compound consists of cis-MoO22+ molybdenyl units that are bridged to neighboring molybdenyl moieties by selenate anions and by a bridging oxo anion. These dimeric units are joined by selenite anions to yield zigzag one-dimensional chains that extended down the c-axis. Individual chains are polar with the C2 distortion of the Mo(VI) octahedra aligning on one side of each chain. However, the overall structure is centrosymmetric because neighboring chains have opposite alignment of the C2 distortion. Upon heating Ag4(Mo2O5)(SeO4)2(SeO3) looses SeO2 in two distinct steps to yield Ag2MoO4. Crystallographic data: (193 K; MoKα, λ=0.71073 A): orthorhombic, space group Pbcm, a=5.6557(3), b=15.8904(7), c=15.7938(7) A, V=1419.41(12), Z=4, R(F)=2.72% for 121 parameters with 1829 reflections with I>2σ(I). Ag2(MoO3)3SeO3 was synthesized by reacting AgNO3 with MoO3, SeO2, and HF under hydrothermal conditions. The structure of Ag2(MoO3)3SeO3 consists of three crystallographically unique Mo(VI) centers that are in 2+2+2 coordination environments with two long, two intermediate, and two short bonds. These MoO6 units are connected to form a molybdenyl ribbon that extends along the c-axis. These ribbons are further connected together through tridentate selenite anions to form two-dimensional layers in the [bc] plane. Crystallographic data: (193 K; MoKα, λ=0.71073 A): monoclinic, space group P21/n, a=7.7034(5), b=11.1485(8), c=12.7500(9) A, β=105.018(1) V=1002.7(2), Z=4, R(F)=3.45% for 164 parameters with 2454 reflections with I>2σ(I). Ag2(MoO3)3SeO3 decomposes to Ag2Mo3O10 on heating above 550 °C.
Synthesis and structural, spectroscopic and magnetic studies of two new polymorphs of Mn(SeO3)·H2O
Larranaga, Aitor,Mesa, Jose L.,Pizarro, Jose L.,Pena,Olazcuaga, Roger,Arriortua, Maria I.,Rojo, Teofilo
, p. 3686 - 3697 (2005)
Two new manganese(II) selenite polymorphs with formula Mn(SeO 3)·H2O have been synthesized by slow evaporation from an aqueous solution. The crystal structure of both compounds (1) and (2) have been solved from X-ray diffraction data. The structure of (1) was determined from single-crystal X-ray diffraction techniques. The compound crystallizes in the Ama2 space group, with a=5.817(1), b=13.449(3), c=4.8765(9)A and Z=4. The structure of (2) has been solved from X-ray powder diffraction data. This phase crystallizes in the P21/n space group with unit-cell parameters of a=4.921(3), b=13.121(7), c=5.816(1)A, β=90.03(2)° and Z=4. Both polymorphs exhibit a layered structure formed by isolated sheets of MnO6 octahedra and (SeO3) 2- trigonal pyramids in the (010) plane. These layers, which contain one manganese and selenium atom crystallographically independent, are formed by octahedra linked between them through the selenite oxoanions. The difference of both compounds consists in the stacking of the layers along the b-axis. The IR spectra show the characteristic bands of the selenite anion. Studies of luminescence performed at 6 K and diffuse reflectance spectroscopy have been carried out for both phases. The Dq and Racah (B and C) parameters, from luminescence and diffuse reflectance spectroscopy, are Dq=705, B=750, C=3325cm-1 for (1) and Dq=720, B=745, C=3350cm-1 for (2). The ESR spectra of both compounds are isotropic with g-values of 1.99(1). Magnetic measurements indicate the presence of antiferromagnetic couplings in both phases. The J-exchange parameters have been estimated by fitting the experimental magnetic data to a model for square-planar lattice. The values obtained are J/k=-0.83, -0.91 K and J′/k=-0.97, -1.20 K, for polymorphs (1) and (2), respectively.
Pressure-induced structural deformations in SeO2
Grzechnik, Andrzej,Farina,Lauck,Syassen,Loa,Bouvier
, p. 184 - 191 (2002)
The high-pressure behavior of low-dimensional selenium dioxide SeO2 (P42/mbc, Z = 8) is studied with Raman scattering and synchrotron angle-dispersive X-ray powder diffraction in a diamond anvil cell up to 23 GPa at room temperature. Pressure-induced transformations in this material involve a sequence of structural distortions of the chain structure. The transformation occuring above 7.0 GPa is due to symmetry lowering to space group Pbam (Z = 8) without major changes of the crystal lattice dimensions and coordination around the Se atoms. Like in the ambient pressure polymorph, the structural unit is a SeO3E polyhedron, where E is a Se non-bonded electron lone pair, or an irregular tetrahedron with the O atoms and Se lone pair at the vertices. Further structural transitions above 17 GPa are likely to be the result of additional distortions leading to monoclinic symmetry of the crystal structure. All transformations are reversible with little hysteresis.
