(C(5)Me(5))(2)Sm (2 equiv) reacts with Ph(2)EEPh(2) to give (C(5)Me(5))(2)SmEPh(2) (E : P, 1; As, 2), while (C(5)Me(5))(2)Sm(THF)(2) (2 equiv) reacts with Ph(2)EEPh(2) to give (C(5)Me(5))(2)Sm(EPh(2))(THF) (E : P, 3; As, 4). 3 and 4 are also available from the reactions of 1 and 2 with THF. 3 and 4 undergo further reaction to produce the THF ring-opened products (C(5)Me(5))(2)Sm[O(CH2)(4)EPh(2)](THF) (E : P, 5; As, 6). (C(5)Me(5))(2)Sm (4 equiv) reacts with Ph(2)EEPh(2) to give the mixed-valent (C(5)Me(5))(2)Sm(mu-EPh(2))Sm(C(5)Me(5))(2) (E : P, 7; As, 8). These compounds are also available from the reaction of 1 and 2 with (C(5)Me(5))(2)Sm. The X-ray crystal structure of 2, crystallized from hexanes (P2(1)/n; a 26.188(24) Angstrom, b = 9.911(10) Angstrom, c = 23.280(23) Angstrom, beta = 97.150(12)degrees V = 5995(2) Angstrom(3), D-calcd = 1.488 Mg/m(3); Z = 8; T = 156 K), revealed, in addition to a conventional seven-coordinate bent metallocene geometry with 2.698 Angstrom Sm-C(C(5)Me(5)) and 2.970 Angstrom Sm-As average distances, two very different Sm-As-C(Ph) angles, 74.2 and 118.7 degrees 0. As a result, one phenyl group is closer to the metal (2.901 Angstrom minimum Sm-C distance). 4, crystallized from toluene (P2(1)/n; a 10.713(9) Angstrom, b = 14.143(11) Angstrom, c 21.620(16) Angstrom, beta = 101.08(6)degrees, V = 3215(4) Angstrom(3), D-calcd = 1.492 Mg/m(3); Z = 4; T = 163 K), and 6, crystallized from-hexanes (P2(1)/n; a 9.3958(16) Angstrom, b = 22.245(3) Angstrom, c 17.931(3) Angstrom, beta = 96.497(11)degrees, V = 3724(1) Angstrom(3), D-calcd = 1.416 Mg/m(3); Z = 4; T = 163 K), have conventional eight-coordinate, bent metallocene structures.