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.
Navegar
3 resultados
Resultados da Pesquisa
Item Vibrational spectroscopic characterization of the phosphate mineral phosphophyllite – Zn2Fe(PO4)2 4H2O, from Hagendorf Süd, Germany and in comparison with other zinc phosphates.(2013) Cipriano, Ricardo Augusto Scholz; Frost, Ray Leslie; Xi, Yunfei; Graça, Leonardo Martins; Lagoeiro, Leonardo Evangelista; López, AndrésThis research was undertaken on phosphophyllite sample from the Hagendorf Süd pegmatite, Bavaria, Germany. Chemical analysis was carried out by Scanning Electron Microscope in the EDS mode and indicates a zinc and iron phosphate with partial substitution of manganese, which partially replaced iron. The calculated chemical formula of the studied sample was determined to be: Zn2(Fe0.65, Mn0.35)P1.00(PO4)2- .4(H2O). The intense Raman peak at 995 cm^-11 is assigned to the m1 PO4^3- symmetric stretching mode and the two Raman bands at 1073 and 1135 cm^-1 to the m3 PO4^3- antisymmetric stretching modes. The m4 PO4^3- bending modes are observed at 505, 571, 592 and 653 cm^-1 and the m2 PO4^3- bending mode at 415 cm^-1. The sharp Raman band at 3567 cm^-1 attributed to the stretching vibration of OH units brings into question the actual formula of phosphophyllite. Vibrational spectroscopy enables an assessment of the molecular structure of phosphophyllite to be assessed.Item Vibrational spectroscopic characterization of the sulphate mineral leightonite K2Ca2Cu(SO4)4 2H2O : implications for the molecular structure.(2013) Frost, Ray Leslie; López, Andrés; Xi, Yunfei; Cipriano, Ricardo Augusto Scholz; Graça, Leonardo Martins; Lagoeiro, Leonardo EvangelistaThe mineral leightonite, a rare sulphate mineral of formula K2Ca2Cu(SO4)4.2H2O, has been studied using a combination of electron probe and vibrational spectroscopy. The mineral is characterized by an intense Raman band at 991 cm^-1 attributed to the SO4^-2 m1 symmetric stretching mode. A series of Raman bands at 1047, 1120, 1137, 1163 and 1177 cm^-1 assigned to the SO4^-2 m3 antisymmetric stretching modes. The observation of multiple bands shows that the symmetry of the sulphate anion is reduced. Multiple Raman and infrared bands in the OH stretching region shows that water in the structure of leightonite is in a range of molecular environments.Item A vibrational spectroscopic study of the borate mineral takedaite Ca3(BO3)2.(2014) Frost, Ray Leslie; López, Andrés; Xi, Yunfei; Graça, Leonardo Martins; Cipriano, Ricardo Augusto ScholzWe have studied the mineral takedaite Ca3(BO3)2, a borate mineral of calcium using SEM with EDX and vibrational spectroscopy. Chemical analysis shows a homogeneous phase, composed of Ca. Boron was not detected. A very intense Raman band at 1087 cm^-1 is assigned to the BO stretching vibration of BO3 units. Additional Raman bands may be due to isotopic splitting. In the infrared spectrum, bands at 1218 cm^-1 and at 1163, 1262 and 1295 cm^-1 are assigned to the trigonal borate stretching modes. Raman bands at 712 and 715 cm^-1 are assigned to the in-plane bending modes of the BO3 units. Vibrational spectroscopy enables aspects of the molecular structure of takedaite to be assessed.