Pr4V5Si4O22, a new praseodymium vanadium oxosilicate with chevkinite structure, has been prepared by heating PrOCL/V2O5/NH4Cl in an evacuated silica tube; the source of silicon is the reaction tube. It crystallizes in the monoclinic space group C2/m(No. 12) with cell dimensions a = 13.410(2), b = 5.5998(9), c = 11.027(3) Å, β = 100.57(2)°, V = 814.0(5) Å3, and Z = 2, Dcalc = 5.23 g/cm3. The structure consists of PrO8 bicapped trigonal prisms, VO6 octahedra, and Si2O7 pyrosilicate groups. This compound has vanadium oxide layers which are similar to the rutile structure; the V-V distances across the shared octahedral edges are 2.7999 Å and vanadium ions are reduced to show average valence of +3.2.