RESUMO
An in situ high-pressure X-ray diffraction study was performed on Ag2S nanosheets, with an average lateral size of 29 nm and a relatively thin thickness. Based on the experimental data, we demonstrated that under high pressure, the samples experienced two different high-pressure structural phase transitions up to 29.4 GPa: from monoclinic P21/n structure (phase I, α-Ag2S) to orthorhombic P212121 structure (phase II) at 8.9 GPa and then to monoclinic P21/n structure (phase III) at 12.4 GPa. The critical phase transition pressures for phase II and phase III are approximately 2-3 GPa higher than that of 30 nm Ag2S nanoparticles and bulk materials. Additionally, phase III was stable up to the highest pressure of 29.4 GPa. Bulk moduli of Ag2S nanosheets were obtained as 73(6) GPa for phase I and 141(4) GPa for phase III, which indicate that the samples are more difficult to compress than their bulk counterparts and some other reported Ag2S nanoparticles. Further analysis suggested that the nanosize effect arising from the smaller thickness of Ag2S nanosheets restricts the relative position slip of the interlayer atoms during the compression, which leads to the enhancing of phase stabilities and the elevating of bulk moduli.
RESUMO
In the title centrosymmetric dinuclear nickel complex, [Ni(2)(C(22)H(30)N(4)O(2))(NO(3))(2)], each of the two Ni(II) atoms has a distorted octa-hedral geometry, defined by two N atoms and two O atoms from the macrocyclic ligand and two O atoms from a chelating nitrate anion. The two Ni atoms are bridged by two phenolate O atoms, forming a four-membered Ni(2)O(2) ring.
RESUMO
In the title compound, [Cd(NO(3))(2)(C(22)H(30)N(2)O(4))], the Cd(II) atom is eight-coordinated by two amine N atoms and two O atoms from the 5,6:19,20-dibenzo-1,4,11,14-tetra-oxa-8,17-diaza-cyclo-eicosane ligand and four O atoms from two nitrate groups. The coordination geometry about Cd is antiprismatic. One nitro O atom is disordered equally over two positions.
