A new nonlinear optical crystal calcium fluoroborate (Ca-5(BO3)(3)F) has been grown successfully using LiF as a flux for the first time. Phase diagram of the pseudobinary Ca-5(BO3)(3)F-LiF system within the composition range from 10 to 60 wt% LiF was investigated by X-ray powder diffraction and differential thermal analysis. Our experiments demonstrated that the composition of LiF from 15 to 35 wt% was beneficial to the growth of Ca-5(BO3)(3)F crystals in Ca-5(BO3)(3)F-LiF system. Transmission spectrum was recorded from 185 to 3000nm, which showed that the UV cutoff for Ca-5(BO3)(3)F crystal was about 190nm. Second-harmonic generation efficiency was measured from Kurtz's powder technique, which indicated that Ca-5(BO3)(3)F could be phase matchable, and second-harmonic generation efficiency of Ca-5(BO3)(3)F was about two times as large as that of KDP. Ca-5(BO3)(3)F has potential application as a nonlinear optical material in UV region. (c) 2006 Elsevier B.V. All rights reserved.