WF(6) reacts with phosphines R(3)P forming 1:1 compounds. With R=P(CH(3))(3) the coordination around the tungsten atom is capped trigonal prismatic, with R=P(CH(3))(2)C(6)H(5) the coordination is capped octahedral, as established by single-crystal structure determinations: [(CH(3))(3)P--WF(6)]: a=752.5(21), b=945.7(24), c=629.8(18) pm. beta=110.36(13) degrees , space group Cm, Z=2; [(CH(3))(2)(C(6)H(5))P--WF(6)]: a=762.2(2), b=1123.5(2), c=2647.5(6) pm, space group Pbca, Z=8. [(CF(3)CH(2))(2)N--WF(5)] reacts smoothly with P(C(6)H(5))(3) forming known P(C(6)H(5))(3)(F)(2) and [(CF(3)CH(2))(2)N--WF(4)--P(C(6)H(5))(3)], a stable, green, molecular species, identified among other methods with an crystal structure determination: a=914.9(1), b=956.0(1), c=1449.8(2) pm, alpha=7.642(4), beta=81.648(3), gamma=81.519 degrees , space group P$\bar 1$, Z=2.