calcium dichloride tetra urea was prepared by the reaction of calcium chloride with urea in aqueous solution. the crystals are monoclinic, a= 7.633, b= 12.45 1, c= 8.118 ?,? = 113.17, z = 4, space group p 2,/a. the crystal structure was determined by single crystal x-ray methods and refined to r= 0.041. the calcium atoms are coordinated to four oxygen atoms of urea and to two chloride ions. the...

in this paper, the structure of a new 16-membered macrocyclic schiff base compound n,n′-(3,3′-dimethoxy-2,2′-(propane-1,3-diyldioxy)dibenzylidene)propane-1,3-diamine, c22h26n2o4 (1), derived from 1,3-propanediamine and 3,3′-dimethoxy-2,2′-(propane-1,3-diyldioxy)dibenzaldehyde has been studied by single crystal x-ray diffraction, dft calculations at b3lyp/6-31g** and ft-ir spectroscopy. the titl...

A coordinate-invariant generalization of the Lyddane-Sachs-Teller relation is presented for polar vibrations in materials with monoclinic and triclinic crystal systems. The generalization is derived from an eigendielectric displacement vector summation approach, which is equivalent to the microscopic Born-Huang description of polar lattice vibrations in the harmonic approximation. An expression...

sr6nb10o30–nb2o5 nanocomposite was synthesized in 2m naoh aqueous solution. a stoichiometric 1:1 sr:nb molar ratio hydrothermal method at 120°c was used to synthesize this nanocomposite. sr(no3)2 and nb2o5 were used as raw materials. the synthesized nanomaterials were characterized by powder x-ray diffraction (pxrd) technique. it was found that sr6nb10o30 was crystallized in tetragonal crystal ...

the synthesis and single-crystal x-ray structure determination of the title compound (dinitrato) (1,4,8,11 -tetra-azaandecane) lead(ii) is described. crystals are monoclinic, p2 /ca= 10.271 (2)?,b= 13.524(4) ?,c= 11.298(6) ?,?=94.68(3),2=4,r,rw, 0.036 and 0.041, respectively. the lead atom is eight-coordinate [pb-n, 2.44 (2) - 2.55 (1)], [pb-0,2.87 (1) - 3.06 (2)].

The mercury (II) complex, Hg (Meca2en)I2 (1), containing bidentate Schiff base ligand  Meca2en = N,N′-bis[(E)-2-benzylidenepropylidene]ethane-1,2-diamine, has been synthesized and characterized by elemental analyses (CHN) and 1H-NMR spectroscopy. The crystal structure of 1 was determined using single-crystal X-ray diffraction. Structural investigation shows that 1 crystallizes in a monoclinic s...