The crystal structure of bromoform, CHBr3

Abstract

The crystal structure of bromoform has been determined by the X-ray diffraction method at about -20 °C. There are two molecules per cell in the structure with hexagonal space group P63 (C6). Unit-cell constants are a= 6"335 + 0"003 and c= 7.214+ 0-003 /~,. The structure is statistically disordered, with molecules oriented upwards and downwards along the c axis at random. The order parameter w was found to be nearly ½ and hence the symmetry of the crystal can approximately be represented by P63/m (C26~).The structure is isomorphous with that of iodoform, while it is quite different from that of chloroform.

A New High-Pressure Polar Phase of Crystalline Bromoform: A First-Principles Study

“…The van der Waals force here is mainly the dispersion forces originated by the instant molecular dipole interactions. 35 The PDOS of the β, γ, and ε phases with increasing pressure are shown in Figure 9 From the calculated energy band structures, it is clearly seen that the γ-CHBr 3 exists as an insulator in the pressure range from 1 to 90 GPa (see Figure 8b), and the ε-CHBr 3 begins to metalize at 130 GPa (see Figure 8c). With the increase of pressure, the bands become more dispersive, the hybridization among C s, p and Br s, p states increase.…”

“…It is also characterized by the coexistence of strong intramolecular and weak intermolecular bondings, implying that the electrons strongly locate at the intramolecular space. The van der Waals force here is mainly the dispersion forces originated by the instant molecular dipole interactions …”

Intermolecular potentials for CH4, CH3F, CHF3, CH3Cl, CH2Cl2, CH3CN, and CO2

“…In addition we have performed supermolecule calculations (basis set: (9,5,1)1 [5,3,1]) in order to compare E~~F with the present model. The results are depicted in Fig.…”

Compression and Probing C−H···I Hydrogen Bonds of Iodoform under High Pressure by X-ray Diffraction and Raman Scattering

“…The early X-ray diffraction studies [10][11][12] of iodoform at ambient pressure and room temperature suggested that it belongs to the space group P6 3 , although a few reports showed the structure of iodoform should be P6 3/m with two molecules per unit cell. 13,14 Almost all spectral studies of CHI 3 have been interpreted in terms of the polar P6 3 structure. [15][16][17][18] Previous studies of iodoform include Raman, infrared, and electrical measurements at high pressure and low temperature.…”