The crystal structure of deuteroammonia between 2 and 180 K by neutron powder profile refinement

Hewat, A.W.; Riekel, C.

doi:10.1107/s0567739479001340

Cited by 109 publications

(92 citation statements)

References 4 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…solid ammonia (2.55Å) [17] and other alkali and alkali earth amides (1.99-2.42Å for Na, Rb, Ca and Sr amide) [18][19][20]. The refined value is, however, in good agreement with the earlier neutron diffraction studies [8] as well as theoretical calculations [10].…”

Section: Structural Featuressupporting

confidence: 80%

The crystal structure of LiND2 and Mg(ND2)2

Sørby

Nakamura

Brinks

et al. 2007

Journal of Alloys and Compounds

View full text Add to dashboard Cite

Section: Structural Featuressupporting

confidence: 80%

The crystal structure of LiND2 and Mg(ND2)2

Sørby

Nakamura

Brinks

et al. 2007

Journal of Alloys and Compounds

View full text Add to dashboard Cite

“…Neutron diffraction [24,25] and x-ray diffraction [26] studies of crystalline ammonia-d0 and ammoniad3 agree about the solid being of the cubic space group. P2i3(T4), with four molecules per unit cell on the sites of C3 symmetry.…”

Section: The Gasmentioning

confidence: 78%

Vapor Pressure Isotope Effects in Liquidand Solid Ammonia

King

Popowicz

et al. 1989

Zeitschrift Für Naturforschung A

View full text Add to dashboard Cite

Dedicated to Professor Jacob Bigeleisen on the occasion of his 70tli birthdayThe H/D and 14N/15N vapor pressure isotope effects in liquid and solid ammonia have been measured at temperatures between 163 K and 243 K. The isotopic vapor pressure data have been fitted to T ln (P' P) = A/T-B for the liquid/liquid, liquid/solid and solid/solid ranges of temperature. The triple points are; 195.41 K (45.49 torr) for 14NH3, 198.96 K (48.35 torr) for 14ND3, and 195.58 K (48.83 torr) for 15NH3. The isotopic difference in the vapor pressures of NH3 and ND3 at temper atures between 195.41 K and 198.96 K is nearly independent of temperature within the present experimental uncertainty. The phase ratios of the reduced partition function ratios, / it,//gas and /soi//gas, deduced from these results are well represented by Tin (fc/fg) = A/T-B. Molecular forces in the liquid and solid ammonias are discussed using a simple cell and a 4-molecular unit cell model, respectively. The librational motions in the liquid are almost as highly hindered as they are in the solid, but the directionality of the external forces on nitrogen atoms in liquid ammonia is not as well defined as in the solid.

show abstract

“…As a starting point in interpreting these data, it's useful to compare our phase III data with the known structures of the two ordered crystalline phases I and IV. Radial distribution functions for these data were calculated using the published crystal structures 7,8 . In order to correct for the density difference between our measurement of phase III and those of the published structures, the lattice parameters were scaled (using constant multiples of 1.0578 for phase IV and 0.954 for phase I) to give an equal atomic density as compared with our phase III measurement.…”

Section: Resultsmentioning

confidence: 99%

“…Ammonia shares some similarities with H 2 O in that it solidifies into a series of H-bonded "molecular ices", at least two of which exhibit orientational disorder of their molecules 4,5 . Of the three solid phases I, II and III on the liquidus up to at least 20 GPa 6 only the lowest pressure phase I (found on freezing below ~0.3 GPa) is ordered 7 . The phase diagram in Fig 1 shows the thermodynamic relations between these phases and the higher pressure, ordered, phase IV.…”

Section: Introductionmentioning

confidence: 99%