A compound is provided that has the formula: Ln4-x-zBxDzM2-n-yAnByO9, where Ln comprises La, Ce, Pr, Nd, Pm, Sm, or a mixture thereof; x is 0 to about 2; D is La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, or a mixture thereof, where: D is not equal to Ln; if D is La, Ce, Pr, Nd, Pm, Sm, or a mixture thereof, then z is 0 to less than 4; if D is Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, or a mixture thereof, then z is 0 to about 2; M comprises Ga, Al, or a combination thereof; A comprises Fe, In, or a combination thereof; n is 0 to about 1; y is 0 to about 1; and x+y is greater than 0. In one embodiment, a composition is generally provided that includes a silicon-containing material and such a boron-doped refractory compound.