5 documents found, page 1 of 1
Raman, infrared and near-infrared spectroscopic characterization of the herderi...
Frost, Ray Leslie; Cipriano, Ricardo Augusto Scholz; López, Andrés; Xi, Yunfei; Queiroz, Camila de Siqueira; Belotti, Fernanda MariaNatural single-crystal specimens of the herderite–hydroxylherderite series from Brazil, with general formula CaBePO4(F,OH), were investigated by electron microprobe, Raman, infrared and near-infrared spectroscopies. The minerals occur as secondary products in granitic pegmatites. Herderite and hydroxylherderite minerals show extensive solid solution formation. The Raman spectra of hydroxylherderite are characte...
Infrared and Raman spectroscopic characterization of the carbonate mineral welo...
Frost, Ray Leslie; Xi, Yunfei; Cipriano, Ricardo Augusto Scholz; Belotti, Fernanda Maria; Cândido Filho, MauroThe mineral weloganite Na2Sr3Zr(CO3)6_3H2O has been studied by using vibrational spectroscopy and a comparison is made with the spectra of weloganite with other carbonate minerals. Weloganite is member of the mckelveyite group that includes donnayite-(Y) and mckelveyite-(Y). The Raman spectrum of weloganite is characterized by an intense band at 1082 cm_1 with shoulder bands at 1061 and 1073 cm_1, attributed to...
Infrared and Raman spectroscopic characterization of the borate mineral coleman...
Frost, Ray Leslie; Xi, Yunfei; Cipriano, Ricardo Augusto Scholz; Belotti, Fernanda Maria; Cândido Filho, MauroColemanite CaB3O4(OH)3_H2O is a secondary borate mineral formed from borax and ulexite in evaporate deposits of alkaline lacustrine sediments. The basic structure of colemanite contains endless chains of interlocking BO2(OH) triangles and BO3(OH) tetrahedrons with the calcium, water and extra hydroxide units interspersed between these chains. The Raman spectra of colemanite is characterized by an intense band a...
The phosphate mineral sigloite Fe3+Al2(PO4)2(OH)3 7(H2O), an exception to the p...
Frost, Ray Leslie; Xi, Yunfei; Cipriano, Ricardo Augusto Scholz; Belotti, Fernanda Maria; Cândido Filho, MauroThe secondary phosphate mineral sigloite Fe3+Al2(PO4)2(OH)3_7H2O is the exception to the rule that phosphate mineral paragenesis is related to the final phase of hydrothermal mineralization at low temperatures. Sigloite was formed as an oxidation pseudomorph after paravauxite, during the last supergene paragenetic stage. We have studied the secondary phosphate mineral sigloite Fe3+Al2(PO4)2(OH)3_7H2O using vibr...
A vibrational spectroscopic study of the phosphate mineral churchite (REE)(PO4)...
Frost, Ray Leslie; López, Andrés; Cipriano, Ricardo Augusto Scholz; Xi, Yunfei; Cândido Filho, MauroVibrational spectroscopy has been used to study the rare earth mineral churchite of formula (REE)(PO4)- _2H2O. The mineral contains a range of rare earth metals including yttrium depending on the locality. The Raman spectra of churchite-(REE) are characterized by an intense sharp band at 984 cm_1 assigned to the m1 ðPO3_ 4 Þ symmetric stretching mode. A lower intensity band observed at around 1067 cm_1 is attri...