Synthesis, Crystal Structure, Optical, Magnetic and Thermal Properties of (NH4)2Mn[B2P3O11(OH)2]Cl

New alkaline-earth amidosulfates and their unexpected decomposition to S4N4

The amidosulphates Mg(NH₂SO₃)₂·4H₂O (P2₁/c), Mg(NH₂SO₃)₂·3H₂O (P1̄), Ca(NH₂SO₃)₂·4H₂O (C2/c), Ca(NH₂SO₃)₂·H₂O (P2₁2₁2₁), Sr(NH₂SO₃)₂·4H₂O (C2/c), Sr(NH₂SO₃)₂·H₂O (P2₁/c) and Ba(NH₂SO₃)₂ (Pna2₁) could be obtained as cm-sized crystals from aqueous solutions of the corresponding metal carbonates, hydroxides and amidosulphonic acid, respectively, by careful control of the crystallisation conditions. β-Sr(NH₂SO₃)₂ (Pc) and α-Sr(NH₂SO₃)₂ (P2₁) could be obtained by careful thermal dehydration of Sr(NH₂SO₃)₂·H₂O. Their crystal structures were determined by single-crystal XRD and revealed a rich structural diversity with a significant tendency to form non-centrosymmetric crystals. The compounds were characterised by powder XRD, FT-IR, Raman and UV/vis spectroscopy and thermogravimetry. Temperature programmed single-crystal XRD, powder XRD and Raman spectroscopy, as well as DFT calculations were employed to aid the interpretation of vibrational and thermal properties. For the first time, SHG measurements were performed on metal amidosulphates, revealing the SHG intensities of β-Sr(NH₂SO₃)₂ and Ba(NH₂SO₃)₂ that were comparable to quartz and KDP. Thermal decomposition was additionally studied by the preparation of reaction intermediates, serendipitously revealing the formation of S₄N₄ as the decomposition product. This unprecedented reaction represents the first sulphur nitride synthesis process that neither employs a sulphur halide nor elemental sulphur.

Fluoroborophosphates: a family of potential deep ultraviolet NLO materials

A series of new fluoroborophosphates obtained by combining BO₃F or BO₂F₂ with a PO₄ tetrahedron exhibit short UV absorption edges and display second-harmonic generation signals.

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.

Gd4(BO2)O5F – a gadolinium borate fluoride oxide comprising a linear BO2 moiety

Gadolinium borate fluoride oxide Gd4(BO2)O5F crystallises in space group Pmmn (no. 59, a = 1574.6(4), b = 381.42(7), c = 660.88(11) pm, 565 refl., 28 parameters, R 1 = 0.039, wR 2 = 0.128, twin refinement) and comprises linear BO2 − anions between closely packed [GdO] layers formed by OGd4 tetrahedra and terminated by oxygen and fluorine atoms. The crystal structure’s relationship with the NiAs type is illustrated. The Raman spectrum recorded on a single crystal of Gd4(BO2)O5F comprises a single peak at 1364 cm−1 assigned to the only Raman-active vibrational mode ν s of the linear triatomic O–B–O units besides very weak peaks at 805 and 2083 cm−1 (presumably the respective δ and ν as modes).