Mossbauer spectra of hexanuclear iron-sulfur basket clusters （α）Fe6S6（PEt3）4（SR）2 and （b）Fe6S5（μ-Sph）（PBS3）4（Sph）2 have been measured. The data have been measured. The data have been fitted sucessfully with a least-squares fitting computer program. The Mossbauer parameters measured at 77K are as follows

for clusters （α）

Fe1: 8=0. 458±0. 004mm/s

ΔEQ = 0. 805±0. 004mm/s

A = 63. 0±3%; Fe1 :δ=0. 286±0. 004mm/s

ΔEQ = 0. 849 ±0. 004mm/s

A = 37. 0±3%; and for clusters（b）

Fe1 : δ=0. 529±0. 004mm/s

ΔEQ = 0. 782±0. 004mm/s

A=68. 2±3% ; FeI:δ=0. 335±0. 004mm/s

ΔEQ = 0. 781±0. 004mm/s

A = 31. 8±3%. The isomer shifts δ are relative to α-Fe. Using an empirical formula of the iso-mer shift 8 and the mean oxidation states for Fe atoms in tetrahedron FeS4 δ=1.44-0. 43s

it can be deduced that for clusters（α）

.FeI is in +2. 2 and Fe I in ±2. 6; and for clusters（b）

Fe I is in +2 and Fe I in +2. 5.