Abstract: Nonlinear optical materials, methods of crystal growth, and devices employing such materials satisfy the general formula (&Sgr;i=1-3M&agr;i1)(&Sgr;j=1-3M&bgr;j2)(&Sgr;k=1-6M&ggr;k3)B14O25  Formula 1 wherein M1, M2, and M3 are mono-, di, or tri-valent metal ions respectively; wherein (&Sgr;i=1-3&agr;i)=X and ranges from 0 to 2, (&Sgr;j=1-3&bgr;j)=Y and ranges from 0 to 4, and (&Sgr;k=1-6&ggr;k)=Z and ranges from 0 to 2, and wherein X+Y+Z=4.0. Other nonlinear optical compounds according to this invention also generally satisfy Formula 2 through 7 below: (&Sgr;j=1-3M&bgr;j2)B14O25, where (&Sgr;j=1-3&bgr;j)=4  Formula 2 M42B14O25  Formula 3 (&Sgr;i=1-3M&agr;i1)(&Sgr;k=1-6M&ggr;k3)B14O25  Formula 4 where (&Sgr;i=1-3&agr;i)=2, and (&Sgr;k=1-6&ggr;k)=2.