EM - Escola de Minas
URI permanente desta comunidadehttp://www.hml.repositorio.ufop.br/handle/123456789/6
Notícias
A Escola de Minas de Ouro Preto foi fundada pelo cientista Claude Henri Gorceix e inaugurada em 12 de outubro de 1876.
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2 resultados
Resultados da Pesquisa
Item SEM, EDX and Raman and infrared spectroscopic study of brianyoungite Zn3(CO3,SO4)(OH)4 from Esperanza Mine, Laurion District, Greece.(2015) Frost, Ray Leslie; López, Andrés; Wang, Lina; Cipriano, Ricardo Augusto Scholz; Sampaio, Ney PinheiroThe mineral brianyoungite, a carbonate–sulphate of zinc, has been studied by scanning electron microscopy (SEM) with chemical analysis using energy dispersive spectroscopy (EDX) and Raman and infrared spectroscopy. Multiple carbonate stretching modes are observed and support the concept of non-equivalent carbonate units in the brianyoungite structure. Intense Raman band at 1056 cm_1 with shoulder band at 1038 cm_1 is assigned to the CO32_ m1 symmetric stretching mode. Two intense Raman bands at 973 and 984 cm_1 are assigned to the symmetric stretching modes of the SO4 2_ anion. The observation of two bands supports the concept of the non-equivalence of sulphate units in the brianyoungite structure. Raman bands at 704 and 736 cm_1 are assigned to the CO32_ m4 bending modes and Raman bands at 507, 528, 609 and 638 cm_1 are assigned to the CO32_ m2 bending modes. Multiple Raman and infrared bands in the OH stretching region are observed, proving the existence of water and hydroxyl units in different molecular environments in the structure of brianyoungite. Vibrational spectroscopy enhances our knowledge of the molecular structure of brianyoungite.Item A Raman and infrared spectroscopic study of the sulphate mineral aluminite Al2(SO4)(OH)4 7H2O.(2015) Frost, Ray Leslie; López, Andrés; Cipriano, Ricardo Augusto Scholz; Wang, LinaThe mineral aluminite has been studied using a number of techniques, including scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDX) and Raman and infrared spectroscopy. Raman spectroscopy identifies multiple sulphate symmetric stretching modes in line with the three sulphate crystallographically different sites. Raman spectroscopy also identifies a low intensity band at 1069 cm 1 which may be attributed to a carbonate symmetric stretching mode, indicating the presence of thaumasite. The observation of multiple bands in this m4 spectral region offers evidence for the reduction in symmetry of the sulphate anion from Td to C2v or even lower symmetry. The Raman band at 3588 cm 1 is assigned to the OH unit stretching vibration and the broad feature at around 3439 cm 1 to water stretching bands. Water stretching vibrations are observed at 3157, 3294, 3378 and 3439 cm 1. Vibrational spectroscopy enables an assessment of the molecular structure of aluminite to be made.