Physicochemical Problems of Mineral Processing, 41 (2007), 101-105 Fizykochemiczne Problemy Mineralurgii, 41 (2007), 101-105 Tolga DEPCI * , Gülhan ÖZBAYOĞLU * , Ayşen YILMAZ ** THE EFFECT OF DIFFERENT STARTING MATERIALS ON THE SYNTHESIS OF LITHIUM TRIBORATE Received April15, 2007; reviewed; accepted May 7, 2007 Lithium triborate (LiB 3 O 5 ) was synthesized using different starting materials. The effect of these materials on the phase purity of LiB 3 O 5 was investigated in each case. Identification and characterizations of the products were carried out by powder X-ray diffraction (XRD) and infrared (IR) analyses. The present study showed that the starting materials play an important role in the synthesis of lithium triborate with respect to phase impurity. Key words: lithium triborate, solid state, XRD analysis, IR analysis INTRODUCTION Lithium triborate, LiB 3 O 5 , is a newly developed nonlinear optical crystal which is chemically stable, mechanically robust and not hygroscopic. It shows thermoluminescence properties. The synthesis and characterization of lithium triborate (LiB 3 O 5 ) have been investigated and reported in the literature (Mazetti 1926; Rollet and Bouaziz 1955; Sastry and Hummel 1958; König and Hoppe 1978; Betourne and Touboul 1997; Massot et al., 1989; Zhong and Tang 1996; Morcyc and Ptak 1999; Almedia et al., 2001). It is difficult to obtain LiB 3 O 5 as a pure compound. During the synthesis stage, some lithium borate compounds like tetraborate (Li 2 B 4 O 7 ), pentaborate (LiB 5 O 8 ), lithium octaborate (Li 2 B 8 O 13 ) can be present in the lithium triborate phase (Sabharwal et al., 2003, 2004; Özdemir et al., 2004; Ardıçoğlu et al., 2006). The purity of lithium triborate is important in the usage of LiB 3 O 5 as a thermoluminescent material, as the impurities may influence the intensity of glow curve. * Department Mining Engineering, Middle East Technical University, 06531, Ankara, Turkey. ** Department of Chemistry, Middle East Technical University, 06531, Ankara, Turkey.