Neutron diffraction refinement of the crystal structure of potassium copper chloride dihydrate, K2CuCl4.2H2O

Structure of 2RbCl.CuCl2.2H2O

“…The distorted octahedral coordination around Cu 2+ consists of two Cl(l) and two C1(2) ions, and two water molecules. The order of the bond lengths is Cu--CI(1) > Cu--CI(2) > Cu--O, which is consistent with the bond-length order in the 2KC1.CuC12-2H20 (Chrobak, 1934;Chidambaram et al, 1970) and 2NH4CI.CuC12"2H20 (Chrobak, 1934 …”

“…170 (14) C (7)A is comparable with 3.116 (5)A for 2KC1.CuC12-2H20 (Chidambaram et al, 1970) and 3.146 (2)A for 2NH4CI'CuClz'2H20 (Bhakay-Tamhane et al, 1980). 2RbC1.…”

“…CuC12.-2H20, 3.364 A (Bhakay-Tamhane et al, 1980). The average distance between the K ÷ and C1-ions in 2KC1-CuC12-2H20, 3.320/~ (Chidambaram et al, 1970), is shorter than those between the monovalent cation and C1-ion in the 2RbC1.CuC12.2H20 and 2NHaC1-CuC12-2H20 crystals. Since the ionic radii reported for the ions with eight coordination are 1.51, 1.61 (Shannon, 1976)and 1.66,A, (Khan & Baur, 1972) for K ÷, Rb ÷ and NH2-, respectively, the interionic distances estimated by using 1.81/~ for the ionic radius of C1- (Shannon, 1976) become 3.32, 3.42 and 3.47 A for the K+--C1 -, Rb+--CI -and NH4+--C1 -pairs, respectively.…”

Structural changes, thermodynamic properties,1H magic angle spinning NMR, and14N NMR of (NH4)2CuCl4·2H2O

“…The A + ions are placed in the almost cubic cavities formed by the tetrahedrons. 11,12 Crystals containing Mn 2+ , Ca 2+ , and Ni 2+ ions form the second of these two classes with triclinic symmetry and the space group P 1 . The (NH 4 ) 2 CuCl 4 $2H 2 O crystal, which is an example of the former, exhibits a structural phase transition from the point group 4/mmm to the point group 4(bar)2m at 200 K. [13][14][15] In addition, two different phase transitions at approximately 383 K and 413 K were observed in the DC electric conductivity measurements reported by Narsimlu et al 16 At room temperature, (NH 4 ) 2 CuCl 4 $2H 2 O forms a tetragonal structure with space group P4 2 /mnm, as shown in Fig.…”

Disorder of ammonium ions in diammonium tetrachlorocuprate dihydrate, (NH4)2CuCl4.2H2O: a high-precision neutron diffraction study

“…2H20 (space group P42/mnm), high-precision neutron diffraction work has been reported so far only on KECUC14.2H20 (Chidambaram et al, 1970). Starting with the heavy-atom coordinates reported for the K salt, the H positional parameters were located using a preliminary Fourier map, derived by using the program FORDAP (Zalkin, 1962, unpublished) which indicated clear, sharp peaks for the protons of the water molecules.…”