The Crystal Structure Study of Li5B4.
Abstract
A study has been made of the crystal structure of Li5B4 by X-ray, neutron powder diffraction techniques and NMR (Nuclear magnetic resonance) measurements. The crystal structure thus determined is rhombohedral (R3) in its short-range ordered state and bcc (I23) in its statistically disordered (long-range) state. The boron atomic arrangement consists of a coplanar triangular cluster of four boron atoms which are situated at the vertices and the center of the triangle. This boron atomic arrangement has no precedent either in metal-borides or boron-hydrides. There is a strong indication that: (1) electrons on the boron atoms at the vertices are partially transferred (approx. 1.3 electrons) to the boron atom at the center of the triangle in Li5B4; and (2) the amount of electron transfer increases with temperature rise. Lithium atoms, on the other hand, cluster in a bitetrahedral form (two tetrahedrons sharing a common face) with five lithium atoms occupying the vertices. This lithium atomic arrangement is in part similar to the hexagonal structure of lithium at low temperature. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 22, 1977
- Accession Number
- ADA044545
Entities
People
- F. E. Wang
- J. R. Holden
- M. A. Mitchell
- R. A. Sutula
Organizations
- Naval Ordnance Laboratory