The crystal structure of (NH 4 ) 4 [Mo 8 O 24+x (O 2 ) 2-x (H 2 O) 2 ]. 4 H 2 O (x = 0.8) has been determined from single-crystal X-ray diffraction data. The yellow compound crystallizes in the monoclinic space group P2 1 /n with a = 10.427(3)A, b = 7.914(5)A, c = 18.103(3) A, β = 96.10(2)°, V = 1485.5(9) A 3 and Z = 2. Full-matrix least-squares refinement of 213 structural parameters gave R(F) = 0.034 (R w (F) = 0.042) for 2630 observed [I > 3σ(I)], independent reflections. The formula implies that part of the diaquatetracosaoxodiperoxooctamolybdate(VI) ions have been replaced by diaquahexacosaoxooctamolybdate(VI) ions and/or diaquapentacosaoxomonoperoxooctamolybdate(VI) ions (substitutional solid solution). The centrosymmetric [Mo 8 O 24 (O 2 ) 2 (H 2 O) 2 ] 4- anion consists of six MoO 6 octahedra and two MoO 5 (O 2 ) pentagonal bipyramids, sharing edges. Selected bond distances: Mo-O peroxo 1.940(9)A-1.964(10) A, Mo=O terminal 1.681(6) A-1.719(6) A, Mo-O bridging 1.751(5) A-2.429(5) A and (O-O) peroxo 1.462(13) A. Mo...Mo edge-sharing is 3.244(1) A-3.494(1) A and Mo...Mo corner-sharing is 3.833(1) A and 4.123(1) A.
[1]
J. Songstad,et al.
Studies on Peroxomolybdates. IX. The Crystal Structure of Potassium Diperoxoheptamolybdate(VI) Octahydrate, K6Mo7O22(O2)2.8H2O.
,
1972
.
[2]
A. Lindberg,et al.
Studies on Peroxidomolybdates. II. Potassium Peroxidomolybdates Crystallizing from Aqueous Solution. A Preliminary Report.
,
1969
.
[3]
A. Balaban,et al.
Studies on Peroxomolybdates. V. The Crystal Structure of Tetramminezinc(II) Tetraperoxomolybdate(VI), [Zn(NH3)4] [Mo(O2)4].
,
1969
.
[4]
A. Müller,et al.
Studies on Peroxidomolybdates. I. The Crystal Structure of Potassium mu-oxido-Bis(oxidodiperoxidoaquomolybdenum(VI)) Dihydrate, K2[(H2O)(O2)2OMoOMoO(O2)2(H2O)](H2O)2.
,
1968
.
[5]
G. Francis,et al.
Studies on Peroxidomolybdates. III. Unit Cell Dimensions for Two Peroxidoheptamolybdates.
,
1968
.