[1] [1] P. Xu, C. T. Xia, F. Wu, X. Li, Q. L. Sai, G. Q. Zhou, and X. D. Xu, Chin. Opt. Lett. 10, 021601 (2012).

[2] [2] L. Tang, H. P. Xia, P. Y. Wang, J. T. Peng, and H. C. Jiang, Chin. Opt. Lett. 11, 061603 (2013).

[3] [3] X. Zhang, L. Fei, J. Shi, and M. Gong, Phys. B: Condens. Matter 406, 2616 (2011).

[4] [4] Z. G. Xia and R. S. Liu, J. Phys. Chem. 116, 15604 (2012).

[5] [5] G. Ju and Y. Hu, Opt. Laser. Tech. 44, 39 (2011).

[6] [6] D. Zhao and F. F. Li, Acta. Crystallogr. Sect. E 66, i64 (2010).

[7] [7] V. B. Mikhailik, H. Kraus, and P. Dorenbos, Phys. Status. Solidi. Papid Res. Lett. 3, 13 (2008).

[8] [8] R. Shannon, Acta Crystallogr. Sect. A 32, 751 (1976).

[9] [9] T. W. Kuo and T.M. Chen, J. Electrochem. Soc. 157, J216 (2010).

[10] [10] W. J. Liu, D. Wang, Y. Wang, J. Zhang, and H. Tao, J. Amer. Ceram. Soc. 96, 2257 (2013).

[11] [11] E. Pavitra and G. Seeta, Phys. Chem. Chem. Phys. 14, 11296 (2012).

[12] [12] X. Zhang and H. J. Seo, J. Alloy. Compd. 503, L14 (2010).

[13] [13] G. Blasse, J. Solid. State. Chem. 62, 207 (1986).