Transition Metal Selenite Halides: A Fascinating Family of Magnetic Compounds

Polytypism of Ln(SeO3)(HSeO3)·2H2O compounds: synthesis and crystal structure of the first monoclinic modification of Nd(SeO3)(HSeO3)·2H2O, DFT calculations and order/disorder description

Compounds with the general formula Ln³⁺(SeO₃)(HSeO₃)·2H₂O, where Ln = Sm³⁺, Tb³⁺, Nd³⁺ and Lu³⁺, are characterized by orthorhombic symmetry with space group P2₁2₁2₁ and unit-cell parameters in the ranges a ∼ 6.473-6.999, b ∼ 6.845-7.101, c ∼ 16.242-16.426 Å. Light-purple irregularly shaped crystals of a new monoclinic polytype of neodymium selenite Nd(SeO₃)(HSeO₃)·2H₂O have been obtained during a mild-condition hydrothermal synthesis. The monoclinic unit-cell parameters are: a = 7.0815 (2), b = 6.6996 (2), c = 16.7734 (5) Å, β = 101.256 (1)°, V = 780.48 (6) ų; space group P2₁/c. The crystal structures of Nd(SeO₃)(HSeO₃)·2H₂O polymorphs show order-disorder (OD) character and can be described using the same OD groupoid family, more precisely a family of OD structures built up from two kinds of non-polar layers (category IV). The first monoclinic maximum degree order (MDO) structure (MDO1-polytype) with space group P2₁/c can be obtained when the inversion centre is active in the L_2n-type layers, while the second MDO structure (MDO2-polytype) is orthorhombic with space group P2₁2₁2₁ and can be obtained when the [2₁--] operation is active in the L_2n-type layers. The structural complexity parameters and DFT calculations of both polytypes show that the polytype structures are extremely close energy-wise and almost equally viable from the point of total energy of the structure.

NaCo2(SeO3)2(OH): competing magnetic ground states of a new sawtooth structure with 3d7 Co2+ ions

We report the high-pressure synthesis and a comprehensive study of NaCo2(SeO3)2(OH) sawtooth chain structure using bulk magnetic properties and neutron scattering.

Unveiling electronic and magnetic properties of Cu3(SeO3)2Cl2and Cu3(TeO3)2Br2oxohalide systems via first-principles calculations

Here, we report a theoretical investigation of the electronic and magnetic properties of two oxohalide compounds, namely Cu₃(SeO₃)₂Cl₂and Cu₃(TeO₃)₂Br₂, using density functional theory (DFT). These layered systems are characterized by two inequivalent Cu sites, with CuO₄and CuO₄X(X= Cl, Br) environments, respectively. A new magnetic model is proposed through the calculation of the magnetic exchange couplings. Our study discloses the participation of the Se and Te lone-pairs to the long-range magnetic order, providing potential key informations for future chemical design of original magnetic systems.

The crystal structure of Ba 2 Mn(SeO3)2Cl2 containing 1 ∞[Mn(SeO3)2Cl2]4− chains

Ba 2 Mn(SeO3)2Cl2, orthorhombic, Pnnm (no. 58), a = 6.7685(5) Å, b = 12.8618(10) Å, c = 5.4685(4) Å, V = 476.06(6) Å3, Z = 2, R gt (F) = 0.0191, wR ref (F2) = 0.0854, T = 298(2) K.

CCDC no.: 2076756

Molecular inorganic polymers: synthesis and crystal structures of KCl72H2SeO3 and CsCl7H2SeO3

KCl72H2SeO3 and CsCl7H2SeO3 have been synthesized using solution evaporation methods from aqueous solution. Both compounds are monoclinic (P2/n and P21/c) and demonstrate new structure types. One symmetrically unique SeO(OH)2 molecule is present in each structure. SeO(OH)2 molecules via strong hydrogen bonds form chains in KCl72H2SeO3 and layers in ?sCl7H2SeO3. The structures of KCl72H2SeO3 and CsCl7H2SeO3 can be described as consisting of ionic KCl chains and CsCl layers incorporated into the covalent- and hydrogen-bonded H2SeO3 matrix. To the best of our knowledge, the cases when selenious acid acts as a contributor to the molecular building blocks of salt-inclusion structures are not known to date.

Influence of the alkali cation size on the Cu2+ coordination environments in (AX)[Cu(HSeO3)2] (A=Na, K, NH4, Rb, Cs; X=Cl, Br) layered copper hydrogen selenite halides

Using solution evaporation techniques, we succeeded in preparation of new members essentially extending the layered copper hydrogen selenite family, (AX)[Cu(HSeO3)2] with A = Na, K, Rb, Cs, and NH4, and X = Cl and Br. Bromides and chlorides are isostructural in the family of described new compounds crystallizing in three different structure types. (NaX)[Cu(HSeO3)2] and (KX)[Cu(HSeO3)2] (X = Cl, Br) are monoclinic, whereas (AX)[Cu(HSeO3)2] (A = NH4, Rb, Cs; X = Cl, Br) are orthorhombic. Upon the enlargement of the A + ionic radii inserted in the interlayer between the neighboring [Cu(HSeO3)2] slabs, the effective distance is increasing and results in essential elongation of the apical Cu-X (X = Cl, Br) distances. Three different types of CuO4 X n (n = 0–2) polyhedra are formed. The observed trend is an interesting example of the chemical tuning of the Cu2+ coordination environments.

Pb2Cd(SeO3)2X2 (X = Cl and Br): two halogenated selenites with phase matchable second harmonic generation

The second harmonic generation (SHG) efficiencies of Pb₂Cd(SeO₃)₂X₂ (X = Cl and Br) are higher than that of commercial KDP (KH₂PO₄) and their laser damage thresholds are 30 times more than that of AGS (AgGaS₂).

Synthesis and structural variety of first Mn and Bi selenites and selenite chlorides

Single crystals of new Mn2[Bi2O](SeO3)4 (I), MnBi(SeO3)2Cl (II), MnIIMnIII(SeO3)2Cl (III), Mn5(SeO3)2Cl6 (IV), and Mn4(Mn5,Bi)(SeO3)8Cl5 (V) have been synthesized by chemical vapour transport and hydrothermal methods. They have been structurally characterized by single crystal X-ray diffraction analysis. The compounds II–V are the first Mn selenite chlorides, while the I, II and V compounds are the first Bi-containing Mn oxoselenites. Structural relationships of the new phases with other compounds are discussed. An overview of the mixed-ligand MnO m Cl n polyhedra in inorganic compounds is given.