Arthur H. Reis, S. W. Peterson, D. M. Washecheck
1976
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0
Influential Citations
15
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Journal
Inorganic Chemistry
Abstract
The oxidation of potassium tetracyanoplatinate(II) in the absence of halide ions results in the formation of bronze needles of K/sub 1.75/Pt(CN)/sub 4/ . 1.5H/sub 2/O stoichiometry. The structure of this partially oxidized material consists of parallel one-dimensional noncollinear chains involving a commensurate repeat unit of 11.865 A. Thus the unit cell contents as deduced from single crystal x-ray data is formulated K/sub 7/(Pt(CN)/sub 4/)/sub 4/ . 6H/sub 2/O and is stoichiometric. This material crystallizes in the triclinic space group P anti 1 with a = 10.323 (14), b = 9.285 (13), c = 11.865 (17) A, ..cap alpha.. = 77.31 (3), ..beta.. = 114.85 (5), ..gamma.. = 73.84 (2)/sup 0/, and Z = 4. The structure was solved by a combination of Patterson, Fourier, and least-squares refinement techniques to an R/sub F/ = 0.050 for the 1840 observed reflections for which F/sub 0/ less than 3 sigma F/sub 0/. There are three inequivalent Pt atoms in the chain and two Pt--Pt bond distances of 2.967 (1) and 2.976 (1) A. The average twist angles of the cyanide ligands of the tetracyanoplatinate planes are 45.3 (5) and 49.8 (3.7/sup 0/). An extensive network of K/sup +/ ionic bonding and hydrogen bondedmore » water molecules knit the material together orthogonal to the chain direction. The chain distortion is shown to be due to Coulombic forces acting between the tetracyanoplatinate anions, located in the asymmetric crystal sites at z = approximately /sup 1///sub 4/ and /sup 3///sub 4/, and the coordinated asymmetric K/sup +/ distribution. The crystallographic analysis leads to the formal oxidation state of +2.25 for Pt in this potassium deficient material and an odd number of electrons per unit cell.« less