Distortion and 17O hyperfine interaction in the centres [GeO4]I,II- in α-quartz

Mineralogy and mineral chemistry of quartz: A review

“…Although the abundance of germanium in nature is low, the isovalent substitution of Ge 4+ for Si 4+ is common. The resulting diamagnetic [GeO 4 ] 0 defect in quartz can be transformed by ionizing radiation at <100 K into two paramagnetic [GeO 4 ]centres (Table S1), which are distinguished by the orbital of the unpaired spin lies along the different O-Ge-O bisectors of the GeO 4 tetrahedron (Mackey, 1963;Isoya et al, 1978;McEachern et al, 1992;McEachern and Weil, 1994 S1; Mackey, 1963;Weil, 1971;Weil, 1984;Rakov et al, 1985;McEachern et al, 1992;McEachern and Weil, 1994 (Weil, 1971;Laman and Weil, 1978;Weil, 1984).…”

“…Although the abundance of germanium in nature is low, the isovalent substitution of Ge 4+ for Si 4+ is common. The resulting diamagnetic [GeO 4 ] 0 defect in quartz can be transformed by ionising radiation at <100 K into two paramagnetic [GeO 4 ] – centres (Table S1), which are distinguished by the orbital of the unpaired spin lying along the different O–Ge–O bisectors of the GeO 4 tetrahedron (Mackey, 1963; Isoya et al , 1978; McEachern et al , 1992; McEachern and Weil, 1994). On warming above 150 K or irradiation at room temperature, the [GeO 4 ] – centres can capture M + ions (Li + , Na + and Ag + ) released from associated [AlO 4 /M + ] 0 centres and form the [GeO 4 /M + ] 0 centres (Table S1; Mackey, 1963; Weil, 1971; Weil, 1984; Rakov et al , 1985; Dickson et al ., 1991; McEachern et al , 1992; McEachern and Weil, 1994; Claridge et al , 2008).…”