Structural Systematics of Rare Earth Complexes. XIX (Hydrated) 1 : 2 Mononuclear Adducts of Lanthanoid(III) Chlorides with 2,2′-Bipyridine and 1,10-Phenanthroline

1999 ◽  
Vol 52 (6) ◽  
pp. 571 ◽  
Author(s):  
Lioubov I. Semenova ◽  
Allan H. White
Keyword(s):  
Rare Earth ◽  
Single Crystal ◽  
Metal Atom ◽  
Room Temperature ◽  
Rare Earth Complexes ◽  
Coordination Environment ◽  
X Ray ◽  
Structure Determinations

Room-temperature single-crystal X-ray structure determinations are recorded for a number of adducts of hydrated lanthanoid(III) trichlorides with 2,2′-bipyridine (‘bpy’) and 1,10-phenanthroline (‘phen’), crystallized from water, methanol or ethanol solutions, containing mononuclear arrays with 1 : 2 Ln/bpy or phen stoichiometry. LaCl3/phen/H2O(1 : 3 : 9), [(phen)2La(OH2)5]Cl3.phen.4H2O, although of overall 1 : 3 LaCl3/phen stoichiometry, has a lattice phen; it is orthorhombic, Pnna, a 19·947(7), b 16·457(5), c 12·213(2) Å, Z = 4; conventional R on |F| was 0·030 for No 2567 ‘observed’ (I >3σ(I)) diffractometer reflections. LaCl3/phen/H2O/MeOH (1 : 2 : 6 : 1), [(phen)2La(OH2)5]Cl3.H2O.MeOH, is triclinic, P 1, a 19·060(3), b 9·252(3), c 8·994(3) Å, α 69·33(3), β 86·81(2), γ 89·66(2)°, Z = 2, R 0·037 for No 5452. LaCl3/bpy/H2O (1 : 2 : 6), [(bpy)2La(OH2)4Cl]Cl2.2H2O, is monoclinic, P 21/c, a 19·389(3), b 9·071(1), c 16·873(2) Å, β 114·10(1)°, Z = 4, R 0·029 for No 4699. All three of these complexes have a nine-coordinate [(N,N′-bidentate)2La(unidentate)5] coordination environment with quasi-2 symmetry; that of the remaining compounds following is eight-coordinate [(N,N′-bidentate)2Ln(unidentate)4]. LuCl3/phen/H2O (1 : 2 : 6), [(phen)2Lu(OH2)4]Cl3.2H2O, is monoclinic, C 2/c, a 11·045(7), b 17·660(6), c 14·474(9) Å, β 92·82(5)°, Z = 4, R 0·042 for No 1695, the Lu lying on a crystallographic 2 -axis. Crystals of LnCl3/phen/H2O(1 : 2 : 4), [(phen)2Ln(OH2)3Cl]Cl2.H2O (Ln = Dy, Er, Y), are triclinic, P 1, a≈ 12·6, b ≈ 10·5, c ≈ 10·4 Å, α ≈ 93·3, β ≈ 109·3, γ ≈ 96·8°, Z = 2, R 0·030, 0·040, 0·052 for No 4221, 5100, 2690 respectively. PrCl3/bpy/H2O/EtOH (1 : 2 : 1 : 0·5), [(bpy)2Pr(OH2)Cl3].½EtOH, is triclinic, P 1, a 13·331(3), b 10·734(2), c 9·758(2) Å, α 63·67(2), β 78·99(2), γ 71·24(2)°, Z = 2, R 0·033 for No 4596, while [(bpy)2Pr(OH2)2Cl2]Cl is monoclinic, C 2/c, a 15·921(15), b 11·314(8), c 14·114(8) Å, β 116·70(6)°, Z = 4, R 0·041 for No 2269. ErCl3/bpy/H2O(1 : 2 : 2 (also)), [(bpy)2Er(OH2)2Cl2]Cl, is cubic, I 23, a 26·032(4) Å, Z = 24, R 0·066 for No 1644. Crystals of LnCl3/phen/H2O/MeOH (1 : 2 : 1 : 1), [(phen)2Ln(OH2)Cl3].MeOH (Ln = La, Pr, Nd, Eu), are monoclinic, P 21/a, a ≈ 13·2, b ≈ 10·7, c ≈ 18·5 Å, β ≈ 102·1°, Z = 4, R 0·054, 0·032, 0·040, 0·054 for No 2872, 4792, 3179, 2847 respectively. LnCl3/bpy/H2O/EtOH (1 : 2 : 1 : 1), [(bpy)2Ln(OH2)Cl3].EtOH (Ln = Nd, Eu), are triclinic, P 1, a ≈ 11·3, b ≈ 10·9, c ≈ 10·4 Å, α ≈ 75·5, β ≈ 89·8, γ ≈ 78·0°, Z = 2, R 0·044, 0·056 for No 4979, 3596 respectively. LaCl3/bpy/EtOH (1 : 2 : 0·5) is binuclear [(bpy)2Cl2La(µ-Cl)2LaCl2(bpy)2].EtOH, monoclinic, P 21/c, a 9·6878(2), b 17·5696(3), c 16·1341(2) Å, β 123·10(1)°, Z = 2, R 0·033 for No 4256. A totally unsolvated array is found for YbCl3/bpy (1 : 2), [(bpy)2YbCl3], monoclinic, P 21/c, a 15·065(8), b 8·598(4), c 16·92(1) Å, β 112·46(5)°, Z = 4, R 0·032 for No 3548, in which, alone, the metal atom is seven-coordinate.

Structural Systematics of Rare Earth Complexes. IX. Tris(nitrato-O,O')(bidentate-N,N')lutetium(III), N,N'-Bidentate Equals 2,2'-Bipyridine or 1,10-Phenanthroline

1996 ◽  
Vol 49 (9) ◽  
pp. 1005 ◽  
Author(s):  
DL Kepert ◽  
LI Semenova ◽  
AN Sobolev ◽  
AH White
Keyword(s):  
Rare Earth ◽  
Single Crystal ◽  
Metal Atom ◽  
Room Temperature ◽  
Rare Earth Complexes ◽  
X Ray ◽  
Twofold Axis ◽  
Metal Atoms ◽  
Structure Determinations

Room-temperature single-crystal X-ray structure determinations of the title compounds, namely, [(ONO2)3Lu(N,N'-bidentate)2], N,N'-bidentate = 'bpy' = 2,2'-bipyridine or 'phen' = 1,10-phenan-throline, are recorded. The complexes are isomorphous with their previously studied lanthanum analogues, being orthorhombic, Pbcn, a 16.517(3), b 9.111(3), c 15.080(3) Ǻ, Z = 4 f.u., and monoclinic, C2/c, a 11.186(7), b 17.785(13), c 12.972(10) Ǻ, β 100.27(5)°, Z = 4 f.u., with R (on |F|) being 0.046 and 0.045 for 1339 and 2097 independent 'observed' (I > 3σ(I)) reflections respectively. The stereochemistries about the metal atoms are also similar, Lu(O2)3(N2)2, the metal atom in each case lying on a crystallographic twofold axis, which also passes through the axis of one of the bidentate nitrate groups; the latter, unlike their counterparts in the La/bpy complexes are not disordered.

Structural Systematics of Rare Earth Complexes. XIV Hydrated 1 : 1 Adducts of Lanthanoid(III) Nitrates with 2,2′:6′,2″-Terpyridine

1999 ◽  
Vol 52 (6) ◽  
pp. 507 ◽  
Author(s):  
Lioubov I. Semenova ◽  
Allan H. White
Keyword(s):  
Rare Earth ◽  
Single Crystal ◽  
Room Temperature ◽  
Rare Earth Complexes ◽  
X Ray ◽  
C 23 ◽  
Structure Determinations

Room-temperature single-crystal X-ray structure determinations are recorded for (hydrated) lanthanoid(III) nitrate/2,2′:6′,2″-terpyridine (‘tpy’) (1 : 1) complexes; all are of the form Ln(NO3)3/tpy/H2O(1 : 1 :x), [(tpy)Ln(O2NO)2(OH2)y](NO3)(.z H2O), and form two series of compounds. For Ln = La(-)Gd, the complexes are [(tpy)Ln(O2NO)2(OH2)3](NO3), the lanthanoid atom being ten-coordinate; crystals are triclinic, P 1, a ≈ 11·8, b ≈ 11·3, c ≈ 8·9 Å, α ≈ 75, β 69, γ ≈ 89°, Z = 2 f.u., conventional R on |F| 0·045, 0·062 for No 4513, 2710 independent ‘observed’ (I > 3σ(I)) diffractometer reflections for Ln = La, Gd respectively. For Ln = Tb(-)Lu, a different form is found: monoclinic, P 21/c, a ≈ 8·8, b ≈ 11·5, c ≈ 23·8 Å, β ≈ 111°, Z = 4, R 0·055, 0·037, 0·056 for No 2427, 3079, 1857 for Ln = Tb, Lu, Y respectively, the form of the complex being [(tpy)Ln(O2NO)2(OH2)2](NO3).2H2O, with nine-coordinate lanthanoid. Crystallization of the Ln = La adduct from methanol yields an adduct of La(NO3)3/tpy/MeOH (1 : 1 : 2) [(tpy)La(O2NO)3(HOMe)2] stoichiometry with 11-coordinate lanthanum. Crystals are triclinic, P 1, a 12·361(2), b 12·244(3), c 7·753(2) Å, α 96·56(2), β 103·22(2), γ 91·16(2)°, Z = 2, R 0·037 for No 6597.

Structural Systematics of Rare Earth Complexes. XVI (‘Maximally’) Hydrated Rare Earth(III) Bromides

1999 ◽  
Vol 52 (6) ◽  
pp. 531 ◽  
Author(s):  
Lioubov I. Semenova ◽  
Peter C. Junk ◽  
Brian W. Skelton ◽  
Allan H. White
Keyword(s):  
Rare Earth ◽  
Single Crystal ◽  
Room Temperature ◽  
Rare Earth Complexes ◽  
X Ray ◽  
Structure Determinations ◽  
First Time

Room-temperature single-crystal X-ray structure determinations carried out on rare earth bromides crystallized from water at room temperature define three series of hydrates LnBr3.nH2O. For Ln = La, Ce, a heptahydrate phase (n = 7) is defined, triclinic P 1, a ≈ 8·6, b ≈ 9·4, c ≈ 8·3 Å, α ≈ 108, β ≈ 99, γ ≈ 72°, isomorphous with the array described for the ‘early’ (Ln = La-Pr) rare earth chlorides, being binuclear [(H2O)7Ln(-Br)2Ln(OH2)7] Br4, Z = 1 dimer; conventional R on |F| were 0·051, 0·042 for 2323, 3451 independent ‘observed’ (I > 3σ(I)) diffractometer reflections respectively. For Ln = Pr(-)Dy, a hexahydrate phase is defined, monoclinic P 2/n, a ≈ 10·0, b ≈ 6·8, c ≈ 8·2 Å, β ≈ 93·5°, Z = 2 f.u., isomorphous with the array defined for the heavier (Ln = Nd, Lu, Y) rare earth chlorides, being [(H2O)6LnBr2] Br, with R 0·029, 0·034 for No 1590, 1388 respectively. For Ln = Ho(-)Lu, Y, an octahydrate is defined for the first time, monoclinic P 21/n, a ≈ 8·1, b ≈ 16·0, c ≈ 10·1 Å, b ≈ 94·0°, Z = 4 f.u., a new array of the form [Ln(OH2)8] Br3 emerging, with R 0·061, 0·048, 0·042 for No 1191, 2402, 1674 respectively, the metal environment being square antiprismatic.

Structural Systematics of Rare Earth Complexes. VI. The Higher Hydrates of the Rare Earth Trichlorides

1994 ◽  
Vol 47 (2) ◽  
pp. 385 ◽  
Author(s):  
CJ Kepert ◽  
BW Skelton ◽  
AH White
Keyword(s):  
Hydrogen Bonding ◽  
Rare Earth ◽  
Single Crystal ◽  
Room Temperature ◽  
Rare Earth Complexes ◽  
X Ray ◽  
Structure Determinations ◽  
The Rare Earth

Single-crystal room-temperature X-ray structure determinations of improved precision are reported for certain higher hydrates of the rare earth trichlorides (LnCl3.7H2O, Ln = La, Pr; LnCl3.6H2O, Ln = Nd, Lu) (triclinic, Pī, and monoclinic, P 2/n, forms respectively) in order to define hydrogen-bonding arrays within the two lattices.

Structural Systematics of Rare Earth Complexes. XV Tris(2,2′:6′,2″-terpyridine)lanthanoid(III) Tris(perchlorate) Complexes

1999 ◽  
Vol 52 (6) ◽  
pp. 519 ◽  
Author(s):  
Lioubov I. Semenova ◽  
Alexander N. Sobolev ◽  
Brian W. Skelton ◽  
Allan H. White
Keyword(s):  
Rare Earth ◽  
Single Crystal ◽  
Coordination Number ◽  
Room Temperature ◽  
Structural Type ◽  
Rare Earth Complexes ◽  
X Ray ◽  
Structure Determinations

Room-temperature single-crystal X-ray structure determinations of the 1 : 3 adducts of the trivalent lanthanoid perchlorates with 2,2′:6′,2″-terpyridine (‘tpy’) as crystallized from acetonitrile are recorded. The Ln = La complex is the only one of its structural type, being modelled as La(ClO4)3/tpy/MeCN/H2O (1 : 3 : 2 :2/3), trigonal P 3c1, Z = 6, a 13·063(7), c 53·04(4) Å, recorded on an interim basis, with conventional R on |F| 0·081 for No 2889 ‘observed’ (I >3σ(I)) reflections. For Ln = Ce, (Pr, Sm,) Eu and, by presumption, other intermediate members, a monosolvate is found, monoclinic P 21/n, a ≈ 9·3, b ≈ 21·1, c ≈ 24·7 Å, β ≈ 91°, Z = 4, R being 0·045, (0·060, 0·049,) 0·047 for No 4420, (4199, 3931,) 3713. The Ln = Eu adduct has also been obtained unsolvated in a form representative of Ln = Eu, Lu and, by presumption, intermediate members, as well as Y, which is monoclinic C 2/c, Z = 4, R being 0·051, 0·044, 0·061 for No 4386, 4407, 3713. All monoclinic systems are of the form [Ln(tpy)3] (ClO4)3(.S), Ln being nine-coordinate, and in the case of the C 2/c phase lying on a crystallographic 2 axis. The Ln = La adduct was modelled with three independent cations, all with crystallographic 3 symmetry, two with their coordination number augmented by the approach of solvent along the 3 axis.

Structural Systematics of Rare Earth Complexes. XVIII (Hydrated) Mononuclear 1 : 1 Adducts of Lanthanoid(III) Chlorides with 2,2′-Bipyridine

1999 ◽  
Vol 52 (6) ◽  
pp. 551 ◽  
Author(s):  
Lioubov I. Semenova ◽  
Brian W. Skelton ◽  
Allan H. White
Keyword(s):  
Rare Earth ◽  
Single Crystal ◽  
Room Temperature ◽  
Rare Earth Complexes ◽  
X Ray ◽  
Structure Determinations ◽  
Binuclear Species

Room-temperature single-crystal X-ray structure determinations are recorded for a number of adducts of hydrated lanthanoid(III) chlorides with 2,2′-bipyridine, ‘bpy’, crystallized from water/ethanol solutions, which contain mononuclear arrays with 1 : 1 Ln/bpy stoichiometry. Extended isomorphous series have been defined pertinent to the heavy end of the Ln series: crystals of LnCl3/bpy/H2O (1 : 1 : 6) ([(bpy)Ln(OH2)6]Cl3), seemingly inclusive of (at least) the range Ln = Ho(-)Lu and Y, are monoclinic, P 21/n, a ≈ 14·2, b ≈ 7·7, c ≈ 17·4 Å, β ≈ 91°, Z = 4, with an eight-coordinate LnN2O6 array; conventional R values on |F| were 0·043, 0·029, 0·057 for No 2435, 3120, 1846 independent ‘observed’ (I > 3σ(I)) diffractometer reflections (Ln = Ho, Lu, Y). Crystals of LnCl3/bpy/H2O (1 : 1·5 : 8) ([(bpy)Ln(OH2)6]Cl3.½bpy.2H2O), seemingly encompassing (at least) the range Ln = Er(-)Lu and Y, are triclinic, P 1, a ≈ 11·7, b ≈ 11·0, c ≈ 10·1 Å, α ≈ 85·8, β ≈ 74·7, γ ≈ 79·5°, Z = 2, R 0·038, 0·033, 0·048 for No 3897, 4377, 3130, and contain similar [(bpy)Ln(OH2)6]3+ cations as does HoCl3/bpy/H2O (1 : 2 : 7), [(bpy)Ho(OH2)6]Cl3.bpy.H2O, orthorhombic, Pbca, a 18·02(2), b 20·06(2), c 15·051(9) Å, Z = 8, R 0·057 for No 3009. By contrast, only sporadic, diverse and unrelated forms are thus far defined among the lighter Ln: EuCl3/bpy/H2O(1 : 1 : 5) ([(bpy)Eu(OH2)4Cl2]Cl.H2O), triclinic, P 1, a 11·506(7), b 11·098(5), c 6·974(8) Å, α 77·35(7), b 85·1(1), γ 89·54(4)°, Z = 2, R 0·063 for No 4633, also contains a mononuclear [(N,N′-bidentate)Ln(unidentate)6] array. PrCl3/bpy/H2O(1 : 1 : 3)(× 4) is a remarkable compound, being 2[(bpy)Pr(OH2)3Cl3] [(bpy)(H2O)2Cl2Pr(µ-Cl)2PrCl2(OH2)2(bpy)].2H2O, triclinic, P 1, a 13·490(4), b 11·121(2), c 10·162(1) Å, α 96·06(1), β 90·08(2), γ 96·43(2)°, Z = 2 f.u., R 0·045 for No 4127, with a mononuclear species of PrCl3/bpy/H2O (1 : 1 : 3) stoichiometry and a binuclear species of 1 : 1 : 2 stoichiometry. A binuclear ethanol solvated array has been characterized for LaCl3/bpy/EtOH (1 : 1 : 2) [(bpy)(EtOH)2Cl2La(µ-Cl)2LaCl2(HOEt)2(bpy)], with eight-coordinate lanthanum; this complex is triclinic, P 1, a 11·426(8), b 10·673(7), c 10·453(7) Å, α 109·60(5), β 113·10(5), γ 105·80(5)°, Z = 1 dimer, R 0·046 for No 2786.

The Rare Earth(III) Nitrate Dimethyl Sulfoxide Adducts [( dmso )nLn(O2NO)3]

1996 ◽  
Vol 49 (9) ◽  
pp. 997 ◽  
Author(s):  
LI Semenova ◽  
BW Skelton ◽  
AH White
Keyword(s):  
Rare Earth ◽  
Single Crystal ◽  
Dimethyl Sulfoxide ◽  
Metal Atom ◽  
Metal Ion ◽  
Room Temperature ◽  
X Ray ◽  
The Subject ◽  
Ion Radius ◽  
The Rare Earth

Adducts [( dmso )nLn(O2NO)3], obtained by the crystallizatior , of lanthanoid (III) nitrate ( Ln (NO3)3.-xH2O) with excess dimethyl sulfoxide (' dmso ') in methanol or ethanol, have been the subject of a series of room-temperature single-crystal X-ray studies, defining more clearly the manner in which stoichiometry and structure systematically vary with change in metal ion radius. All complexes studied are mononuclear, the metal ion being complexed by three bidentate nitrate ligands and a number of dmso ligands , four for La-Sm and three beyond. The array La- Sm is monoclinic C2/c, a ≈ 14.9, b ≈ 15.5, c ≈ 15.5 Ǻ, β ≈ 108.4°, Z = 4 f.u .; the metal atom is disposed on a crystallographic 2 axis, which also passes through one of the nitrate groups. The series Eu -Tm (inclusive also of Y) is monoclinic, P21/n, a ≈ 11.5, b ≈ 12.7, c ≈ 13.6 Ǻ, β ≈ 100°, Z = 4 f.u ., while Yb and Lu are also monoclinic, P21/c, a ≈ 10.0, b ≈ 12.6, c ≈ 16 Ǻ, β ≈ 100.6°, Z = 4 f.u.

Structural Systematics of Rare Earth Complexes. XXII. ('Maximally') Hydrated Rare Earth Iodides

2000 ◽  
Vol 53 (10) ◽  
pp. 867 ◽  
Author(s):  
Kevin C. Lim ◽  
Brian W. Skelton ◽  
Allan H. White
Keyword(s):  
Aqueous Solution ◽  
Rare Earth ◽  
Low Temperature ◽  
Single Crystal ◽  
Room Temperature ◽  
Second Phase ◽  
X Ray ◽  
Structure Determinations ◽  
Trivalent Rare Earth ◽  
Trigonal Prismatic

Low-temperature (c. 153 K) single-crystal X-ray structure determinations, carried out on trivalent rare earth iodides crystallized from aqueous solution at room temperature, have defined two series of hydrates, LnI3.nH2O. For Ln = La–Ho, a nonahydrate phase (n = 9) is defined, orthorhombic Pmmn, a ~ 11.5, b ~ 8.0, c ~ 8.8 Å, Z = 2, the second phase (n = 10), monoclinic P21/c, Z = 4 being defined for Ln = Er–Lu, a ~ 8.2, b ~ 12.8, c ~ 17.1 Å, β ~ 103.7˚. Neither of these phases is isomorphous with any of those pertinent to the previously studied chloride or bromide (hydrated) arrays, nor, unlike those, does the halide (iodide) in any case enter the coordination sphere of the lanthanoid. The n = 9 phase takes the form [Ln(OH2)9]I3, the nine-coordinate lanthanoid environment stereochemistry being tricapped trigonal-prismatic, while the n = 10 phase is [Ln(OH2)8]I3.2H2O, the eight-coordinate lanthanoid environment being square-antiprismatic.

Lewis-Base Adducts of Lead(II) Compounds. XVI. Synthetic and Structural Studies of Some Adducts of 2-Aminomethylpyridine With Lead(II) Compounds

1996 ◽  
Vol 49 (10) ◽  
pp. 1127 ◽  
Author(s):  
JM Harrowfield ◽  
H Miyamae ◽  
BW Skelton ◽  
AA Soudi ◽  
AH White
Keyword(s):  
Single Crystal ◽  
Room Temperature ◽  
Lewis Base ◽  
Structural Studies ◽  
Problem Structure ◽  
Coordination Environment ◽  
X Ray ◽  
The Third ◽  
Structure Determinations ◽  
Centrosymmetric Dimers

Syntheses and room-temperature single-crystal X-ray structure determinations are recorded for 2:1 adducts of 2-aminomethylpyridine ('amp') with lead(II) nitrate and thiocyanate . [(amp)2Pb(NO3)2]2 is triclinic, Pī, a 11.616(4), b 11.145(6), c 7.341(3) Ǻ, α 83.87(4), β 89.17(3), γ 64.12(3)°, Z = 1 dimer ; R was 0.043 for No 3529 independent 'observed' (I > 3σ(I)) reflections. [(amp)2Pb(SCN)2]2 is also triclinic, Pī , a 12.121(9), b 9.301(14), c 8.615(8) Ǻ, α 70.11(10), β 84.00(7), γ 79.38(10)°, Z = 1 dimer (R 0.033 for No 3467). Both complexes are centrosymmetric dimers ; the coordination environment is made up in each case of a pair of N,N°-bidentate bases, one terminally bound anion (O,O°-chelating nitrate or S-bonded thiocyanate ) and bridging anions. In the case of the thiocyanates, these bridge end-on, so that the lead(II) environment is seven-coordinate PbN5S2; in the nitrate, the anion chelates through two of its oxygen atoms, bridging via the third, so that the lead(II) environment is nine-coordinate PbN4O5. A 'problem structure', [(amp)2Pb(ClO4)2], monoclinic, C2/c (?), a 14.528(3), b 8.203(3), c 15.495(6) Ǻ, β 91.14(3)°, Z = 4 f.u ., R 0.044 for No 1775, is also recorded, the crystal seemingly a disordered aggregate of [(N, N′-amp)2Pb(OClO3)2] moieties.

Structural Systematics of Rare Earth Complexes. XX (Maximally) Hydrated Rare Earth Sulfates and the Double Sulfates (NH4)Ln(SO4)2.4H2O (Ln = La, Tb)

1999 ◽  
Vol 52 (6) ◽  
pp. 601 ◽  
Author(s):  
Cameron J. Kepert ◽  
Peter C. Junk ◽  
Brian W. Skelton ◽  
Allan H. White
Keyword(s):  
Rare Earth ◽  
Single Crystal ◽  
Room Temperature ◽  
Rare Earth Complexes ◽  
Two Dimensional ◽  
Sulfate Ions ◽  
X Ray ◽  
Double Sulfate ◽  
Trivalent Rare Earth ◽  
Double Sulfates

Room-temperature single-crystal X-ray studies carried out on trivalent rare earth sulfate hydrates, Ln2(SO4)3.xH2O, crystallized at local ambience suggest the following arrays to be prevalent. For Ln = La, the nonahydrate is found, hexagonal P 63/m, with conventional R on |F| 0·023 for No 1159 ‘observed’ (I >3σ(I)) diffractometer reflections (redetermination). Although for Ln = Ce a similar structure has been previously recorded, we have obtained that adduct as the monoclinic C 2/c, Z = 4, octahydrate, a phase also found for Ln = Lu and diverse representative intermediate lanthanoids: a ≈ 13·6, b ≈ 6·6, c ≈ 18·2 Å, β ≈ 102°; for Ln = Ce (redetermination), Dy, Yb (redetermination), Lu, R was 0·022, 0·035, 0·031, 0·024 for No 3279, 2127, 3008, 3325 respectively. The structures of two lower hydrates adventitiously obtained are also recorded: the pentahydrate for Ln = Ce, monoclinic C 2/c, a 15·741(3), b 9·632(3), c 10·358(3) Å, β 119·72(2)°, Z = 4, R 0·030 for No 3372 (a redetermination), and the trihydrate for Ln = Lu, orthorhombic Cmc21, a 13·527(5), b 18·415(5), c 9·242(7) Å, Z = 8, R 0·040 for No 1743. All structures are infinite polymeric arrays, the lanthanoid atoms being bridged by sulfate ions. Studies are also recorded for the ammonium/trivalent rare earth double sulfate tetrahydrate salts, (NH4)Ln(SO4)2.4H2O, for the (hitherto) extremal members Ln = La, Tb, which are isomorphous with the previously studied Ln = Sm monoclinic P 21/c, Z = 4 array, a ≈ 6·6, b ≈ 19, c ≈ 8·8 Å, β 97°; R 0·035, 0·037 for No 3631, 3337. The array is a two-dimensional polymer, parallel to the ac plane.

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