catena-Poly[[aquabarium(II)]-mu-aqua-bis(mu-2'-carboxybiphenyl-2-carboxylato)]

Samia Djehni1, Fadila Balegroune, Achoura Guehria-Laidoudi

  • 1Laboratoire de Cristallographie-Thermodynamique, Faculté de Chimie, USTHB, BP 32, El-Alia, Bab-Ezzouar 16111, Alger, Algeria.

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Polydentate ligands are most widely used in complexometric titrations because they form more stable complexes with the metal ions than mono- or bidentate ligands due to the chelate effect. Examples of polydentate ligands are ethylenediaminetetraacetic acid (EDTA), crown ethers, and cryptands. The most important feature of optimal polydentate ligands is the ability to form 1:1 complexes in a single-step process. Amino carboxylic acid derivatives are frequently used as complexing agents. EDTA is...
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In most main group element compounds, the valence electrons of the isolated atoms combine to form chemical bonds that satisfy the octet rule. For instance, the four valence electrons of carbon overlap with electrons from four hydrogen atoms to form CH4. The one valence electron leaves sodium and adds to the seven valence electrons of chlorine to form the ionic formula unit NaCl (Figure 1a). Transition metals do not normally bond in this fashion. They primarily form coordinate covalent bonds, a...
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