Rationalization of the Substructures Derived from the Three Fluorite-Related [Li6(MVLi)N4] Polymorphs: An Analysis in Terms of the “Barnighausen Trees” and of the “Extended Zintl–Klemm Concept” - Inorganic 3D Structures - page 106

Fig. 9 (a) The sodalite-type sub-array in Li 7 VN 4 . V(2)N 4 tetrahedra - red , V(1)N 4 tetrahedra -
grey . Light blue atoms are Li(4). (b) The sodium perchlorate sodalite structure. SiO 4 tetrahedra -
red , AlO 4 tetrahedra - green . Light blue atoms are Na. ClO 4 tetrahedra - grey .(c) Sodalite-type
framework in Li 7 VN 4 . V(1)N 4 tetrahedra - grey , V(2)-Li(2) bonds - blue , V(2) atoms - red , Li(2)
atoms - green .(d) The sodalite framework in Na 8 [Al 6 Si 6 O 24 ](ClO 4 ) 2 . ClO 4 tetrahedra - grey ,
Al-Si bonds - blue , Si atoms - red , Al atoms - green

The various drawings are shown in Fig. 9a-d from which it emerges that the
body-centred cubes comprise V(1)N 4 tetrahedra for Li 56 [V(1) 2 V(2) 6 N 32 ] and ClO 4
tetrahedra for sodalite. However, in each case, two icosahedra have been fused to
create an inscribed cuboctahedron to complete the required frameworks.
Many other compounds with this elegant framework also satisfy the electron
requirements: for example, the mineral danalite - Fe 8 [(BeSiO 4 ) 6 ]S 2 [ 31 ], the borate
(B 12 O 24 )(Zn 4 O) 2 [ 32 ] and [Be 6 As 6 O 24 ](LiCl) 2 [ 33 ] in which the sodalite-like III-V
network can be achieved by the unique transfer of six electrons from 6 Li to 6 Be,
which thus becomes 6 C -B, the resulting formula being [ C -He] 6 [( C -B) 6 As 6 O 24 ]

(LiCl) 2 .

3.2.4 Colusite and Germanite

A further detailed search of the database in space group 43 n has revealed the

existence of the two minerals, colusite [ 34 ], Cu 26 [V 2 As 4 Sn 2 ]S 32 , and germanite
[ 35 ] , Cu 26 [Fe 4 Ge 4 ]S 32 . Both are sphalerite-like structures, except that the VS 4 (CuS 4 )

P