Raman spectra of oriented and non-oriented Cu hydroxy-phosphate minerals: Libethenite, cornetite, pseudomalachite, reichenbachite and ludjibaite

摘要

Oriented cornetite [Cu_3PO_4(OH)_3], libethenite [Cu_2PO_4(OH)] and pseudomalachite [Cu_5(PO_4)_2(OH)_4] and non-oriented reichenbachite [Cu_5(PO_4)_2(OH)_4] and ludjibaite [Cu_5(PO_4)_2(OH)_4] minerals from Lubietová and ?pania Dolina dump fields, Banská Bystrica, Slovakia were examined by polarized Raman spectroscopy. The examined minerals display the characteristic vibrational modes of PO_4 and OH groups and further lattice modes. The PO_4 stretching and bending vibrations of the investigated minerals occur between 1150 and 900 cm~(-1) and between 700 and 350 cm~(-1), respectively. On the other hand, the hydroxyl group stretching and bending modes appear above 3350 cm~(-1) and between 900 and 700 cm~(-1), respectively. The lattice vibrations occur below 350 cm~(-1). The different bond distances of the PO_4 groups readily explain the shift of the bands to higher or lower wavenumbers among the studied Cu hydroxy-phosphate minerals.