Description
A Zintl phase, dibarium-tritin-hexaantimonide,
Ba
2Sn
3Sb
6 has been synthesized, and its structure has
been determined by single-crystal XRD methods. It crystallizes
in the orthorhombic space groupdPnma with
a = 13.351(1)? , b=4.4100(5)? , c=24.449(3) ? , and
Z=4 (T=-50°C). The structure of Ba
2Sn
3Sb
6
comprises large channels [010] defined by 30-membered
rings constructed from an anionic framework. This
framework is built up from Sn-centered trigonal pyramids
and tetrahedra, as well as zigzag chains of Sb
atoms. Within the channels reside the Ba2t cations and
additional isolated zigzag Sb–Sb chains. The simultaneous
presence of Sn trigonal pyramids and tetrahedra
implies that Ba
2Sn
3Sb
6 is a mixed-valence compound
whose oxidation state notation can be best represented
as (Ba
2þ)
2[(Sn
II)
2(Sn
IV)(Sb
III)
3(Sb
I)]
2 [(Sb
I)
2]
2 .
