Highly lattice mismatched bismide semiconductor alloys are widely studied now. The thermodynamic stability is one of the main conditions for their use. Spinodal decomposition ranges of A(III)Bi(x)B(1-x)(V) (A(III) = Ga, In; B-V = P, As, Sb), A(III)Bi(x)B(y)(V)C(1-x-y)(V) (A(III) = Ga, In; B-V, C-V = P, As; P, Sb; As, Sb) and InxGa1-xBiyB1-yV (B-V = P, As, Sb) are calculated from 0 degrees C to 1000 degrees C. The cohesive energy, enthalpy of formation, bond stretching and bond bending elastic constants of zinc blende GaBi are calculated. The interaction parameters between compounds when one or two compounds contain Bi are estimated. Spinodal decomposition in A(III)Bi(x)Sb(1-x) (A(III) = Ga, In), A(III)Bi(x)Sb(y)As(1-x-y) (A(III) = Ga, In) and InxGa1-xBiySb1-y is not predicted. There are significant Bi concentration ranges in GaBixAsyP1-x-y, InBixAsyP1-x-y, GaBixSbyP1-x-y, InBixSbyP1-x-y and GaBixSbyAs1-x-y lattice matched to the conventional substrates that are outside spinodal decomposition ranges. The spinodal decomposition ranges of InxGa1-xBiyB1-yV (B-V = P, As) are very wide.