Li–M–X systems have been investigated and crystal structures of several phases determined. Li7NbP4 crystallizes in the antifluorite-type structure (cubic, Fm3m, a=5.996(1) Å, Z=1, R(F)=3.02%). LiNbAs2 and Li4.54V1.22As4 display the blende-type structure, cubic F43m space group (LiNbAs2:a= 6.309(1) Å, Z=2, R(F)=2.12%; Li4.54V1.22As4:a=6.167(1) Å, Z=1, R(F)=1.49%). In all compounds, the transition metal statistically occupies some of the tetrahedral sites with lithium. For Li4.54V1.22As4, one of the octahedral sites of the fcc lattice is partially filled with lithium. This feature is also observed for the homologue compounds Lix(Li3.20Nb0.80)As4 and Lix(Li3.64Ta0.36)As4, 0<x≤4 (F43m, Z=1, a=6.190(3) and 6.184(3) Å, R(F)=1.76 and 3.42%, respectively).