A new non-centrosymmetric borate, K3YB6O12, has been synthesized by solid state reaction techniques, and a K3YB6O12 crystal with dimensions of similar to 40 mm x 30 mm x 10 mm was successfully grown by the top-seeded solution growth method using a K2O-B2O3-KBF4 flux. K3YB6O12 crystallizes in the trigonal space group R32 with cell parameters of a = 13.2202(19) angstrom, c = 30.281(6) angstrom, and Z = 15. In the structure of K3YB6O12, B5O10 groups are bridged by Y3O12 chains and discrete YO6 octahedra via corner-sharing, constructing columns packed side by side in a hexagonal motif along the c-axis to form a three-dimensional framework. The three-dimensional framework affords one-dimensional tunnels of 8-membered rings along the b-axis which are occupied by K atoms. K3YB6O12 melts incongruently at 941 degrees C, and exhibits a short UV cutoff edge at 195 nm. The second harmonic generation effect of K3YB6O12 is weaker than that of KH2PO4. (c) 2012 Elsevier Ltd. All rights reserved.