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Lithium tetraoxobromate(1-) monohydrate, LiBrO4.-H2O, whose perchlorate analog has not yet been described, is found to be isomorphic with NaBrO4.H2O and NaClO4.H2O. Each of the two inequivalent Li ions is coordinated by six O atoms, thus forming distorted octahedra, each of which has three inequivalent Li-O distances. At room temperature, the average Li(1)-O and Li(2)-O distances are 2.150 and 2.164 A, respectively. The perbromate ion displays very nearly regular tetrahedral geometry, although it is not subject to symmetry constraints. At 296 K the average observed Br-O distance is 1.610 (4) A and the average O-Br-O angle is 109.5 (6) degrees, while at 173 K the corresponding values are 1.613 (4) A and 109.5 (7) degrees. The perbromate ion shows rigid-body behavior but the lithium coordination polyhedra do not. At 296 K, the average rigid-body corrected Br-O distance in the perbromate ion is 1.624 (3) A, in excellent agreement with the corresponding value reported for NaBrO4.H2O. Refinement of the two inequivalent H atoms allowed detailed analysis of the hydrogen bonding, which is more extensive than in NaBrO4.H2O or in NaClO4.H2O. The average observed B values for the H atoms [2.9 (3) A2 at 296 K and 2.8 (3) A2 at 173 K] are sufficiently small to suggest that dynamic disordering of the H atoms (determined by magnetic resonance methods for NaClO4.H2O) is not significant in the title salt.

The structure of the title compound consists of columns of Ca ions surrounded by four columns of perbromate ions and four columns of water molecules alternating in pairs. The CaO8 complex was found to be dimensionally similar to corresponding complexes in other simple tetrahydrated calcium salts. The eight coordinating O atoms form a polyhedron which departs only slightly from a (distorted) square antiprism. Each of the crystallographically inequivalent perbromate ions was found to conform to rigid-body behavior while the CaO8 complex did not. Although the perbromate ions depart moderately from regular tetrahedral geometry, the mean Br--O bond length agrees well with previously determined values. Hydrogen bonds in this structure involve water-oxygen acceptors as well as perbromate-oxygen acceptors.

Hexaaquaaluminium(III) bromate trihydrate, [Al(H2O)6](BrO3)3.3H2O, M(r) = 572.84, triclinic, P1, a = 9.536 (2), b = 11.095 (4), c = 9.291 (2) A, alpha = 106.58 (2), beta = 100.42 (2), gamma = 113.01 (2) degrees, V = 818.1 (4) A3, Z = 2, Dx = 2.33 g cm-3, lambda(Mo K alpha) = 0.71073 A, mu = 74.58 cm-1, F(000) = 560, T = 296 K, R = 0.050 for 3777 unique reflections having I greater than sigma 1. The single type of Al ion is coordinated by six inequivalent water O atoms which form a slightly distorted octahedron. The average Al--O distance within the octahedron is 1.872 (11) A. Each of the three inequivalent bromate groups has three inequivalent O atoms. The average Br--O distances and O--Br--O angles for these ions are: 1.652 (25) A and 104.1 (17) degrees for Br(1)O3; 1.650 (9) A and 104.4 (18) degrees for Br(2)O3; 1.643 (9) A and 103.6 (14) degrees for Br(3)O3. The aluminium-oxygen complex conformed to rigid-body behavior but the bromate groups did not. Corrected for rigid-body motion, the average Al--O distance becomes 1.880 (10) A. Least-squares refinement of the positional parameters of the 18 inequivalent H atoms permitted a detailed analysis of the hydrogen bonding.

NaBrO4.H2O, Mr = 184.90, monoclinic, C2/c, a = 15.7575 (19), b = 5.7373 (15), c = 11.3390 (19) A, beta = 111.193 (10)degrees, V = 955.8 (3) A3, Z = 8, Dx = 2.570 g cm-3, lambda(Mo K alpha) = 0.71073 A, mu = 85.2 cm-1, F(000) = 704, T = 296 K, R = 0.039 for 1137 unique reflections having I greater than sigma I. In this structure, there are two inequivalent Na ions, each coordinated by six O atoms. In each of the two types of distorted octahedra, there are three inequivalent Na--O distances; the average Na(1)--O and Na(2)--O distances are 2.379 (10) and 2.405 (23) A, respectively. The perbromate ion in this structure displays very nearly regular tetrahedral geometry, although it is subject to no symmetry constraints; the average observed Br--O distance is 1.601 (4) A, while the average observed O--Br--O angle is 109.5 (9)degrees. These values agree well with previously reported values. The perbromate ion, but neither of the sodium coordination polyhedra, shows rigid-body behavior. The average rigid-body corrected Br--O distance in the perbromate ion is 1.624 (3) A. Refinement of the two inequivalent H atoms permitted detailed analysis of the hydrogen bonding, which is slightly different from that reported for the isomorphic sodium perchlorate monohydrate. Dynamic disordering of the H atoms as detailed by magnetic resonance methods for sodium perchlorate monohydrate is not clearly indicated in our X-ray study of sodium perbromate monohydrate.

[Cu(H2O)6](BrO3)2, Mr = 427.44, cubic, Pa3, a = 10.3240 (6) A, V = 1100.38 (4) A3, Z = 4, Dx = 2.580 g cm-3, lambda (Mo K alpha) = 0.71073 A, mu = 92.32 cm-1, F(000) = 828, T = 296 K, R = 0.038 for 336 unique reflections having I greater than sigma I. The single type of copper ion (site symmetry 3) is coordinated by six water-molecule O atoms, each at an observed distance of 2.079 (4) A, in an array which is virtually regular octahedral, the nominal 90 degree angles measuring 89.95 (15) and 90.05 (15) degrees. Thus, this is not a typical CuII complex in which (consistent with a static Jahn-Teller effect) a distorted octahedral array displays '(2 + 2 + 2)' coordination; rather, it is the sixth strict example of a CuII static structure inconsistent with the Jahn-Teller theorem. The presence of a dynamic Jahn-Teller effect is supported by the data. The single type of bromate ion has an observed Br-O bond length 1.649 (3) A and O-Br-O bond angle 104.17 (15) degrees. The bromate ion was found to manifest rigid-body behavior but, consistent with a dynamic Jahn-Teller effect, the copper-oxygen complex did not. The Br-O bond length corrected for rigid-body motion is 1.663 A. Refinement of the positional parameters of the two inequivalent H atoms permitted a detailed analysis of hydrogen bonding, which occurs principally between the oxygen octahedra and the bromate groups.(ABSTRACT TRUNCATED AT 250 WORDS)

[Ni(H2O)6](BrO3)2, Mr = 422.60, cubic, Pa3, a = 10.2987 (6) A, V = 1092.3 (2) A3, Z = 4, F(000) = 824, Dx = 2.57 g cm-3, lambda(Mo K alpha) = 0.71073 A, mu = 90.79 cm-1, T = 296 K, R = 0.024 for 360 unique reflections having I greater than sigma I. The single type of nickel ion is coordinated by six water-molecule O atoms, each at an observed distance of 2.061 (2) A, in an almost regular octahedral array. The single type of bromate ion has an observed Br--O bond length of 1.655 (2) A and O--Br--O bond angle 104.25 (9) degrees. Both the nickel-oxygen complex and the bromate ion were found to manifest rigid-body behavior. The Ni--O distance corrected for rigid-body motion is 2.065 A, while the corrected Br--O bond length is 1.663 A. Location and refinement of the two inequivalent H atoms permitted a detailed analysis of the hydrogen bonding, which occurs principally between the oxygen octahedron and the bromate groups. This structure is isomorphic to the structures of hexaaquanickel(II) chlorate and hexaaquacobalt(II) bromate which have been reported recently from this laboratory.

[Co(H2O)6](BrO3)2, Mr = 422.83, cubic, Pa-3, a = 10.3505 (7) A, V = 1108.88 (8) A3, Z = 4, Dx = 2.53 g cm-3, lambda(Mo K-alpha) = 0.71069 A, mu = 87.31 cm-1, F(000) = 820, T = 296 K, R = 0.027 for 365 unique reflections having I greater than sigma I. The single type of Co ion is coordinated by six water-molecule O atoms, each at an observed distance 2.095 (2) A, in an array which is regular octahedral within the estimated standard deviations of the relevant angles. The single type of bromate ion has a Br-O bond length 1.653 (2) A and O-Br-O bond angle 104.07 (9) degrees. The cobalt-oxygen complex manifested rigid-body behavior, but the bromate ion did not. The cobalt-oxygen distance corrected for rigid-body motion is 2.099 A. Location and refinement of the two inequivalent H atoms permitted detailed analysis of the hydrogen bonding, which occurs principally between the oxygen octahedra and the bromate groups. This structure is isomorphic to that of hexa-aquanickel(II) chlorate recently reported from this laboratory.

Ni(BrO4)2.6H2O, Mr = 454.61, trigonal, P3, a = 7.874 (1), c = 5.423 (2) A, V = 291.2 (1) A3, Z = 1, D chi = 2.59 g cm-3, lambda(Mo K alpha) = 0.71069 A, mu = 85.36 cm-1, F(000) = 222, T = 296 K, R = 0.029 for 457 unique reflections having I greater than 0. The room-temperature structure is very similar to that reported previously for a sample at 169 K. The water O atoms form a very slightly distorted octahedron about nickel while the perbromate-ion geometry is virtually regular tetrahedral. Both the coordination polyhedron and the perbromate ion were tested and found to behave as rigid bodies. Corrected for rigid-body motion, the Ni--O(2) distance is 2.064 (2) A and the mean Br--O distance in the perbromate ion is 1.629 (3) A. A detailed account of the hydrogen bonding is presented. The structure previously determined at 169 K is most probably not the stable structure at that temperature.