Letter | Published:

A New Metallic Layer Structure

Nature volume 180, pages 14121413 (21 December 1957) | Download Citation

Subjects

Abstract

DURING the course of an investigation into the system manganese/mercury, I confirmed the existence of the intermediate phase Mn2Hg5 reported by Prelinger1 and described its crystal habit and determined the dimensions of its unit cell2. Since then, satisfactory Weissenberg photographs have been obtained from very small crystals (0.01–0.02 mm. in diameter). The only systematic absences observed were 0kl for k odd, which lead to three possible space groups, namely, P4/mbm (D54h), P&4bar;b2 (D72d) and P4bm (C24v). Furthermore, the hk0 and hk2 intensities display the same trend, which is different from that of the hkl intensities. If the ten mercury atoms in the cell are all placed at z = 0 and the four manganese atoms at z = ½, it is apparent that the geometrical structure factor for the first of the three space groups is identical for all reflexions with l = 2n, but the manganese contributions reverse their signs for l = 2n + 1. This arrangement of atoms is only possible in the space group P4/mbm. From packing considerations a structure could be derived which gave good agreement between the observed and calculated intensities. The geometrically derived parameters are u = 0.075 and v = 0.206 for the eight mercury atoms at positions ± (uv0 ; vu0; u + ½,½ − v,0; v + ½, n + ½,0) and u = 0.178 for the manganese atoms at ± (u,u + ½, ½;, u + ½, u,½), the two remaining mercury atoms being situated at special positions (½,0,0) and (0,½,0). Further refinement of these parameters by Fourier methods is under way; the results will be published more fully elsewhere.

Access optionsAccess options

Rent or Buy article

Get time limited or full article access on ReadCube.

from$8.99

All prices are NET prices.

References

  1. 1.

    , Monatsh. Chem., 14, 353 (1893).

  2. 2.

    , Angew. Chem., 67, 208 (1955).

  3. 3.

    , Z. Krist., A, 88, 281 (1934).

Download references

Author information

Affiliations

  1. National Chemical Research Laboratory, South African Council for Scientific and Industrial Research, Pretoria. July 12.

    • J. F. DE WET

Authors

  1. Search for J. F. DE WET in:

About this article

Publication history

Published

DOI

https://doi.org/10.1038/1801412b0

Further reading

Comments

By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.