[4] [4] Yu X, Xu X H, Yang P H, et al. Materials Research Bulletin, 2012, 47(1): 117.

[5] [5] Yang W J, Luo L Y, Chen T M, et al. Chemistry of Materials, 2005, 17(15): 3883.

[6] [6] Kim B S, Song Y H, Jo D S, et al. Materials Research Bulletin, 2012, 47(10): 3015.

[7] [7] Ju G F, Hu Y H, Chen L, et al. Journal of Luminescence, 2014, 146: 102.

[8] [8] Yu X, Xu X H, Yu H L, et al. Materials Research Bulletin, 2012, 47(9): 2696.

[9] [9] Wang Y H, Wang Z Y, Zhang P Y, et al. Materials Letters, 2004, 58(26): 3308.

[10] [10] Yang P H, Yu X, Xu X H, et al. Journal of Solid State Chemistry, 2013, 202: 143.

[11] [11] Russell J K, Giordano D. Geochimica et Cosmochimica Acta, 2005, 69(22): 5333.

[12] [12] Xu X H, Yu X, Zhou D C, et al. Journal of Solid State Chemistry, 2013, 206: 66.

[13] [13] Koker N D. Geochimica et Cosmochimica Acta, 2010, 74(19): 5657.

[14] [14] Giordano D, Potuzak M, Romano C, et al. Chemical Geology, 2008, 256(3-4): 203.

[15] [15] Parc R L, Champagnon B, Dianoux J, et al. Journal of Non-Crystalline Solids, 2003, 323(1-3): 155.