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The reactions of 1,4-bis(phenylthio)butane (L) with Ag(I) salts in varied conditions (varying the solvents, metal-to-ligand ratios, and counteranions) lead to the formation of four new two-dimensional (2D) coordination polymers with different network structures: [Ag(2)L(3)(ClO(4))(2)](infinity) 1, [Ag(2)L(3)(ClO(4))(2) x CH(3)OH](infinity) 2, [[AgL(2)](ClO(4))](infinity) 3, and [AgLNO(3)](infinity) 4. All the structures were established by single-crystal X-ray diffraction analysis. Crystal data for 1: triclinic, P-1, a = 11.0253(9) A, b = 11.3455(9) A, c = 11.5231(9) A, alpha = 93.931(2) degrees, beta = 92.689(2) degrees, gamma = 112.9810(10) degrees, Z = 2. 2: triclinic, P-1, a = 11.9147(13) A, b = 16.1534(17) A, c = 16.2259(17) A, alpha = 74.977(2) degrees, beta = 69.030(2) degrees, gamma = 69.986(2) degrees, Z = 2. 3: triclinic, P-1, a = 12.1617(9) A, b = 12.5054(10) A, c = 13.1547(10) A, alpha = 64.3370(10) degrees, beta =85.938 (2) degrees, gamma = 69.3010(10) degrees, Z = 2. 4: monoclinic, P2(1)/c, a = 5.4032(17) A, b = 16.974(6) A, c = 19.489(6) A, beta = 94.234(6) degrees, Z = 4. In all four complexes, each Ag(I) center has a tetracoordination geometry, and the 2D networks consist of fused large macrometallacyclic ring systems. The "hexagonal" 42-membered rings, Ag(6)L(6), observed in 1 and 2 are nearly identical, which could be considered as unique examples of self-sustaining noninterpenetrated frameworks formed with flexible ligands. The repeating rectangular 28-membered macrometallacycle, Ag(4)L(4), is the basis for the network of 3, in which the perchlorate anions occupy the voids to prevent the ring from collapsing. In 4, columns of the fused rectangular 22-membered rings, Ag(4)L(2)(NO(3))(2), are cross-linked through the L ligands to form a unique 2D network consisting of two types of 22-membered repeating units.

A number of con~positions AZ3+TiZ4+ 0 7 and of related mixed phases were prepared and investigated. For the trivalent lanthanons from Sm to Lu, and for Y, the homogeneous A,Ti207 phases were of the cubic pyrochlore type. Their lattice parameters gave a very good linear relationship when plotted against the Templeton-Dauben radii of A3+. The room-temperature stability region of the pyrochlore titanates at ordinary pressures extends from an Ahrens radius ratio, r(A3+):r(Ti4+), of about 1.22 to about 1.50, taking into account homogeneous mixed phases. The compositions Bi2Ti207, In2Ti207, and Cr,Ti20, were not cubic pyrochlores; the results of an X-ray and neutron examination of Sc2Ti20, indicate that further work is needed to clarify its structural properties.The structures of Lu, Y, Gd, and Snl titanates were refined from X-ray powder data and that of Y,(Ti,,6,Zro.36),07, from neutron powder data. The structure of Er2Ti207 was re-refined from previously published data without significant improvement. The positional parameter of the majority oxygen atom, x(OZ), in A2B207 pyrochlores has been found to increase, and the distortion of the B06 octahedra to decrease, with the increasing r(A3+):y(B4+) ratio. This is in agreement with a similar result obtained earlier from Mossbauer spectra for A2FeSb0, pyrochlores.The variation of the frequencies of the principal absorption bands in the infrared spectra of the titanates has been correlated with ?(A3+). No evidence of ferroelectricity was found in Sm and Er titanates between room temperature and 4.2 OK.The Templeton-Dauben set of empirical crystal radii for trivalent lanthanons has been supplemented by values for Sc, In, TI, and Bi derived from the C-type sesquioxides and the pyrochlores. The selfconsistency and applicability of the expanded set have been tested on several series of isostructural con~pounds.

Fillings and cavities: Three novel pseudo‐octahedral metal–organic frameworks, 1–3, consisting of macrometallacyclic noninterpenetrating meso networks and exhibiting weak antiferromagnetic interactions, have been constructed from CuII centers and structurally flexible R,S‐bis(sulfinyl) ligands. Varying the chain length of ligands is found to control the cavity sizes of the networks.

The cubic pyrochlores Cd,Nb,O,, Cd2Ta,0,. S n 2 N b 2 0 j . S n z T a 2 0 7 . Cd,Sb20,, Ca2Sb,0,, M n 2 S b 2 0 i , PbzSb,O,. and related compounds were prepared and investigated by a number of methods. On heating above 700'. Ca,SbzO,(pyrochlorc) transformed to Ca,Sb,O,(weberitej, while Pb,Sb201(pyrochlore) changed to a rhombohedrally distorted P b 2 S b 2 0 j pyrochlore. Refinement of the crystal structures of Cd,Nb,O, and C d z T a 2 0 , from powderdiffractometer intensities yielded 0.434(2) and 0.434(3) respectively as the best estimates of .\. (O,). Specimens of natural bindheimite and stibiconite were also examined. Stibiconite from San Luis Potosi (Mexico) was shown. on the evidence of its Mossbauer "'Sb spectrum, to contain Sb(V) and Sb(II1) in the approximate ratio of 0.2.BaCd,CI,.5HI0 and BaCd2CI,.2H20 both give powder diffraction patterns of the pyrochlore type. The chlorine could be partially replaced by Br to give mixed crystals BaCd,CI,-,Brl,5H,0 almost up to z = 2.The crystal chemistry of 2-5 oxide pyrochlores and the relationship of the weberite to the pyrochlore phases are discussed. On discute d e la cristallochiniie des pyrochlores oxygknes de type 2-5 ainsi que de la relation entrc les phases pyrochlore et wdberite. Canadian Journal of Chemistry. 50, 3648 (1972) As a sequel to our previous investigations of oxide pyrochlores of compositions A;+B;+O, ( 3 -4 pyrochlores) and Ai+B:+O, ( 1 -5 pyrochlores) (IPS), some corresponding 2-5 pyrochlores have been studied. Minerals of this type (pyrochlore. niicrolite etc.) have been known for a long time. and the discovery of ferroelectricity in Cd2Nb20, (9) initiated a search for similar compounds with unusual dielectric properties. This search has proved disappointing in that it has uncovered but a minuscule number of new ferroelectrics of this structure type. It showed, however, that for some combinations of divalent and pentavalent cations the composition of the pyrochlore (P) phase is not limited to the ideal A,B,O, stoichiometry, while for other combinations oiz!v hypostoichiometric P phases can be prepared by conventional methods. The 2-5 pyrochlores are then best described by the general formula A , + = B 2 0 6 +,. The range of z is determined by the particular combination of A and B. and may include unity. The stability of the P structure can be correlated, for 3-4 pyrochlores, with the ionic size and radius ratio of the cations (10). A similar correlation is less satisfactorv for the 2--5 pyrochlores ( 1 1). Pentavalent cations of suitable size and chemistry are relatively few, and the absence, among divalent elements. of an extensive sequence of closely related ions, such as that formed by the trivalent lanthanons, makes each of the 2-5 P phases more unique. The Can. J. Chem. Downloaded from www.nrcresearchpress.com by 34.208.6.16 on 05/10/18For personal use only.

(1974).The crystalline conformation of polypivalolactone was determined by analysis of the chain conformational energies and it was found that the minimum energy corresponds to a planar tmrzs conformation for the ester group. The result was con~pared to published X-ray data based on fiber diffraction which show a significant deviation from trans planarity. This difference is discussed in terms of the relative energies involved and by comparison with literature crystallographic results of low molecular weight carboxylic esters. It is stressed that because of the paucity of information in fiber diffraction, internal energy considerations are important for assigning internal rotation angles. Crystallographic results for low molecular weight compounds show that deviations greater than 10" from trans planarity are rare for ester groups.J. COR~IBERT, N. V. MIEN, F. BRISSE et R. H. MARCHESSAULT. Can. J. Chem. 52,3742 (1974). On a determine la conformation cristalline de la polypivalolactone par analyse des energies conformationnelles de chaines; on a trouve que l'tnergie minimum correspond a une conformation trans coplanaire pour le groupe ester. Ce rCsultat est compare avec les donnees de rayons-)< publiees, basees sur la diffraction de fibre, qui montrent une deviation notable de la planarite trans. On discute de cette difference en termes d'knergies relatives impliquees et par comparaison avec les resultats cristallographiques rapportes dans la litterature pour des esters carboxyliques de faible poids moleci~laire. On fait remarquer que, dd ail peu d'information de la diffraction des fibres, la consideration d'energie internee est importante pour attribuer les angles de rotation interne. Les resultats cristallographiques pour des composes de bas poids moleculaires montrent que des deviations plus grandes que 10' par rapport a la planarite traits sont rares dans les groupes esters.[Traduit par le journal]