scholarly journals The crystal structure of Rochelle salt (sodium potassium tartrate tetrahydrate NaKC 4 H 4 O 6 . 4H 2 O)

1941 ◽  
Vol 177 (969) ◽  
pp. 251-259 ◽  
Keyword(s):  
Crystal Structure ◽  
Carboxyl Groups ◽  
Water Molecules ◽  
Rochelle Salt ◽  
Sodium Potassium ◽  
Sodium Potassium Tartrate ◽  
Potassium Tartrate ◽  
Tetrahedral Bonding ◽  
Sodium And Potassium ◽  
Continuous Chain

The complete crystal structure of Rochelle salt (sodium potassium tartrate tetrahydrate) has been determined by Fourier and Patterson methods. Some of the difficulties in the application of these methods are discussed. The tartrate molecule is found to lie approximately in three planes, the planes of each half of the molecule being inclined at 60° to the plane of the carbon atoms. The tartrate molecules are bonded to sodium and potassium atoms both directly and through the medium of water molecules. If the water molecules are to preserve their customary tetrahedral ‘ bonding ’ it is necessary to suppose that one of the carboxyl groups of the molecule is also a dipole. A reversal of the continuous chain of carboxyl-water-water dipoles is a possible explanation of the peculiar dielectric properties of the salt.

Hydrated metal complexes of N-(6-amino-3,4-dihydro-3-methyl-5-nitroso-4-oxopyrimidin-2-yl)glycinate: interplay of molecular, molecular–electronic and supramolecular structures

2001 ◽  
Vol 57 (3) ◽  
pp. 317-328 ◽  
Author(s):  
John N. Low ◽  
Jose M. Moreno Sánchez ◽  
Paloma Arranz Mascarós ◽  
M. Luz Godino Salido ◽  
Rafael López Garzon ◽  
...  
Keyword(s):  
Metal Complexes ◽  
Three Dimensional ◽  
Organic Ligands ◽  
Water Molecules ◽  
Molecular Aggregates ◽  
Nitroso Group ◽  
Interatomic Distances ◽  
Vertex Sharing ◽  
Sodium And Potassium ◽  
Continuous Chain

The title anion, (C7H8N5O4)−, L −, forms hydrated metal complexes with a range of metal ions M + and M 2+. Lithium and manganese(II) form finite molecular aggregates [Li(L)(H2O)3] (1) and [Mn(L)2(H2O)4].6H2O (4) in which the molecular aggregates are linked into three-dimensional frameworks by extensive hydrogen bonding. The sodium and potassium derivatives, [Na2(L)2(H2O)3] (2) and [K(L)(H2O)] (3) both form organic–inorganic hybrid sheets in which metal–oxygen ribbons are linked by strips containing only organic ligands: these sheets are linked by hydrogen bonds into three-dimensional frameworks. In (2) the metal–oxygen ribbon is built from pairs of edge-shared trigonal bipyramids linked by water molecules, while in (3) it consists of a continuous chain of vertex-sharing octahedra. The nitroso group in the anion acts as an η1 ligand towards Na+ and as an η2 ligand towards K+. In all cases the anion L − shows the same unusual pattern of interatomic distances as the neutral parent LH.

Some anomalous optical properties of freshly-prepared mixed crystals of the Seignette salts

1924 ◽  
Vol 20 (104) ◽  
pp. 159-172 ◽  
Author(s):  
Harold E. Buckley
Keyword(s):  
Circular Polarization ◽  
Axial Plane ◽  
Continuous Series ◽  
Ammonium Tartrate ◽  
Crystalline Compound ◽  
Remarkable Property ◽  
Sodium Potassium ◽  
Sodium Potassium Tartrate ◽  
Potassium Tartrate ◽  
Rhombic System

The new crystalline compound triphenyl-bismuthine dichloride, described crystallographically by Mr. G. Greenwood (Min. Mag., 1923, vol. 20, p. 123), possesses the remarkable property of exhibiting crossed axial-plane dispersion of the rhombic ‘brookite’ type and circular polarization. For purposes of comparison, the author prepared specimens of the mixed Seiguette salts, which also exhibit crossed axial-plane dispersion together with circular polarization. The Seignette salts, sodium-potassium tartrate and sodium-ammonium tartrato, crystallize each with four molecules of water ill the bisphenoidal class of the rhombic system. They are truly isomorphous and form a continuous series of mixtures. The acute bisectrix for sodium-ammonium tartrate is normal to (001)and for sodium-potassium tartrate normal to (100). For all proportions of mixture containing 5 % and over of sodium-ammonium tartrate, the acute bisectrix is normal to (001).

Sign in / Sign up

Export Citation Format

Share Document