Bis-Hexaaquasodium Decaaqua-Monohydrogen-Hexasodium-Gadolinium-bis-(Nitrilo-Tris-Methylenephosphonate) Tetrahydrate: Synthesis, Structure, Chemical Bonding

Bis-hexaaquasodium decaaqua-monohydrogen-hexasodium-gadolinium-bis-(nitrilo-tris-methylenephosphonate) tetrahydrate [Na(H 2 O) 6 ] 2 [GdNa 6 H(H 2 O) 10 {N(CH 2 PO 3 } 2 ]·4H 2 O (space group P 2 1 / c, Z = 2, a = 11.8168(7) Å, b = 10.5403(9) Å, c = 19.8094(10) Å, β = 94.232(5)) has been synthesized and isolated. The Gd 3+ ion is coordinated in the configuration of an elongated rhombohedron in the environment of two acid residues {N(CH 2 PO 3 ) 3 }. Two rhombohedron’s vertices distant from its center are occupied by nitrogen atoms, and six nearest vertices are occupied by oxygen atoms. Six sodium ions form inorganic bridges P-O-Na-O-P. The structure of the obtained complex is confirmed spectroscopically. XPS data indicate the formation of coordination bonds Gd-N and multiple bonds Gd-O.