Syntheses and structures of CsHo3Te5 and Cs3Tm11Te18 and the electronic structure of CsHo3Te5

Diverse Closed Cavities in Condensed Rare Earth Metal–Chalcogenide Matrixes: Cs[Lu7Q11] and (ClCs6)[RE21Q34] (RE = Dy, Ho; Q = S, Se, Te)

“…Such a trend goes roughly monotonically with the density decrease (identity of atom should be taken into account). For instance, in spite of the closed cavity structural feature of (ClCs 6 )[Dy 21 Se 34 ], the A/RE ratio (3/10.5 = 0.29) and density (6.06 g cm −3 ) are located between those of Cs 3 Tm 11 Te 18 16 and Cs 3 Y 7 Se 12 12 (6.67 and 4.73 g cm −3 ), suggesting a quite loose packing because of the large cavity, which agrees well with the structure feature discussed above. Therefore, this compound also fits in such an A/RE ratio-structure change trend.…”

“…Ternary alkali metal/rare earth metal/chalcogenide compounds (A/RE/Q, Q = S, Se, Te) are fascinating for their complexity and beauty. Up until now, eight types of structures are known and are listed according to their A/RE/Q stoichiometries as following, 1:1:2 (including about 40 compounds, e.g., RbLaSe 2 ), − 3:7:12 (adopted by roughly 10 compounds, e.g., Rb 3 Yb 7 Se 12 ), − 1:3:5 (only 2 examples of CsEr 3 Se 5 and CsHo 3 Te 5 ), 3:11:18 (only found in Cs 3 Tm 11 Te 18 ), 1:5:8 (RbSc 5 Te 8 ), 2:24:36 (as found in a Tm fractional occupied example, K 2 Tm 23.33 S 36 ), 1:1:4 (including 12 compounds, e.g., KCeSe 4 ), − and 1:3:8 (including 4 compounds, e.g., KPr 3 Te 8 ). ,, Note that 1:1:4 and 1:3:8 types of compounds possess Q–Q bonding interactions and are thus excluded from the structure discussion below. Another exception is K 2 Tm 23.33 S 33 in which two types of building units are found as TmS 6 and TmS 7 .…”

“…All of the remaining A/RE/Q compounds have two structural moieties generally, i.e., the positive moiety, discrete interstitial A cation, and the negative moiety, anionic RE/Q substructure constructed by the REQ 6 octahedron building unit. The structural diversity comes from the rich ways that the building unit REQ 6 can be linked by, such as edge-sharing in layered RbLuSe 2 , and edge- and face-sharing in 3D channel Cs 3 Tm 11 Te 18 …”

“…The structural diversity comes from the rich ways that the building unit REQ 6 can be linked by, such as edgesharing in layered RbLuSe 2 , 1 and edge-and face-sharing in 3D channel Cs 3 Tm 11 Te 18 . 16 The majority of A/RE/Q compounds are channel structure (shown below). Interestingly, the size of the channel increases as the increasing of the A/RE ratio.…”