Six new actinide metal thiophosphates have been synthesized by the reactive flux method and characterized by single-crystal X-ray diffraction: CS8U5(P3S10)(2)(PS4)(6) (I), K10Th3(P2S7)(4)(P-S4)(2) (II), K5U(PS4)(3) (III), K5Th(PS4)(3) (IV), Rb5Th(PS4)(3) (V), and CS5Th(PS4)(3) (VI). Compound I crystallizes in the monoclinic space group P2(1)/c with a 33.2897(1) Angstrom, b = 14.9295(1) Angstrom, c = 17.3528(2) Angstrom, beta = 115.478(1)degrees, Z = 8. Compound II crystallizes in the monoclinic space group C2/c with a = 32.8085(6) Angstrom, b = 9.8482(2) Angstrom, c = 27.2972(3) Angstrom, beta = 125.720(1)degrees, Z = 8. Compound III crystallizes in the monoclinic space group P2(1)/c with a = 14.6132(1) Angstrom, b = 17.0884(2) Angstrom, c = 9.7082(2) Angstrom, beta = 108.63(1)degrees, Z = 4. Compound IV crystallizes in the monoclinic space group P2(1)/c with 9.7436(1) Angstrom, b = 11.3894(2) Angstrom, c = 20.0163(3) Angstrom, beta = 90.041(1)degrees, Z = 4, as a pseudo-merohedrally twinned cell. Compound V crystallizes in the monoclinic space group P2(1)/c with a = 13.197(4) Angstrom, b = 9.997(4) Angstrom, c = 18.189(7) Angstrom, beta = 100.77(1)degrees Z = 4. Compound VI crystallizes in the monoclinic space group P2(1)/c with a = 13.5624(1) Angstrom, b = 10.3007(1) Angstrom, c = 18.6738(1) Angstrom, beta = 100.670(1)degrees, Z = 4. Optical band-gap measurements by diffuse reflectance show that compounds I and III contain tetravalent uranium as part of an extended electronic system. Thorium-containing compounds are large-gap materials. Raman spectroscopy on single crystals displays the vibrational characteristics expected for [PS4](3-), [P2S7](4-), and the new [P3S10](5-) building blocks. This new thiophosphate building block has not been observed except in the structure of the uranium-containing compound CS8U5(P3S10)(2)(PS4)(6).