Rock salt–urea–water (1/1/1) at 293 and 117 K

Abstract

The crystal structure of NaCl.CH(4)N(2)O.H(2)O has been determined at 117 K and redetermined at room temperature. It can be described as consisting of alternating ;organic' and ;inorganic' planar layers. While at room temperature the structure belongs to the space group I2, the low-temperature structure belongs to the space group Pn2(1)m. All water O atoms are located on positions with crystallographic symmetry 2 (m) in the room-temperature (low-temperature) structure, which means that the water molecules belong, in both cases, to point group mm2. During the phase transition, half of the urea molecules per unit cell perform a 90 degrees rotation about their respective C-O axes. The other half and the inorganic parts of the structure remain unaltered. The relationship between the two phases is remarkable, inasmuch as no obvious reason for the transition to occur could be found; the internal structures of all components of the two phases remain unaltered and even the interactions between the different parts seem to be the same before and after the transition (at least when looked at from an energetic point of view).

NaCl·CH4N2O·H2O: An Organic–Inorganic Hybrid Ultraviolet Nonlinear Optical Crystal with Optimized Comprehensive Properties

“…36 Its crystal structure was reported in 1963 37 and refined in 2008. 27 The UV and IR transmittance spectra are measured on a crystal slice about 1 mm thick. The result demonstrates that the UV cutoff edge of NaCl•CH 4 N 2 O•H 2 O is about 209 nm, corresponding to an energy band gap of 5.93 eV (Figure 2d).…”

“…The crystal of NaCl·CH 4 N 2 O·H 2 O was first discovered in 1950 . Its crystal structure was reported in 1963 and refined in 2008 . At room temperature, NaCl·CH 4 N 2 O·H 2 O belongs to space group I 2, with cell parameters a = 6.4845(2) Å, b = 5.2362(2) Å, c = 17.3497(5) Å, β = 90.152(2)°, Z = 4.…”

“…NaCl·CH 4 N 2 O·H 2 O single crystals were grown using a simple aqueous method as described by Müller et al NaCl (15.5 g), urea (40.0 g), and water (40 mL) were stirred at 30 °C with a magnetic stirrer until a clear solution had formed. After placing in a refrigerator at −4 °C, large crystal plates with a size of 7 × 8 × 1 mm 3 formed (Figure a).…”

“…Based on the above viewpoints, we used the first-principles high-throughput screening pipeline for nonlinear optical materials (FPHS-NLO) 25,26 27 NaCl (15.5 g), urea (40.0 g), and water (40 mL) were stirred at 30 °C with a magnetic stirrer until a clear solution had formed. After placing in a refrigerator at −4 °C, large crystal plates with a size of 7 × 8 × 1 mm 3 formed (Figure 2a).…”

Iridium(III) products isolated in a reaction of IrCl3 with phenyl 2-pyridyl ketoxime

“…Coordination sphere of each Ir 3+ ion is completed by three terminal chlorido ligands (Ir--Cl bond lengths at 2.337 (2) (7) 162 Symmetry codes: i: x, y þ 1, z; ii: x þ 1, y, z; iii: Àx þ 1, Ày þ 2, Àz þ 1. for Na--Cl coordination bonds in literature (e.g. 2.8381 (7) and 2.8845(7) Å in rock salt-urea-water (1/1/1) at 117 K [12]), to create specific [Ir 2 Na 2 ] units. The coordination sphere of each Na þ cation also includes three acetonitrile ligands (Na--N bond lengths at 2.413(6)-2.461(6) Å range in agreement with the expected values [13]).…”