ISSN:
1572-8862
Keywords:
Alkali-metal-thallium compounds
;
hypoelectronic clusters
;
size factors
;
cluster distortion
;
pentacapped trigonal prisms
;
thallium clusters
;
metallic salts
Source:
Springer Online Journal Archives 1860-2000
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
,
Physics
Notes:
Abstract The title compounds, which are synthesized from be elements, are shown to be isostructural with K8In11 (R3¯c Z=6) and to contain pentacapped trigonal prismatic clusters that have been compressed along the three-fold axes so as to bring the two types of capping atoms within bonding distances. These are arranged in double-ccp layers separated by double alkali--metal layers. Extended Hückel calculations show a substantial energy gap and the end of significant intracluster bonding for the hypoelectronic (by Wade's rules) 18-electron Tl11 7−. Correspondingly, all three compounds are metallic (ρ298 ≈ 400 μΩ · cm) and Pauli-paramagnetic (χM ≈ 4 x 10−4 emu. mol−1, consistent with their formulation as metallic (A +)8Tl11 7− e− phases. Factors thought to be responsible for the cluster distortion, the metallic salt characteristics, and the unusual chemistry of thallium am noted.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01175845
Permalink
