Phasenbeziehungen im System Se-SeCl₄ und die Kristallstruktur einer metastabilen Modifikation von SeCl₄ / Phase Relations in the System Se-SeCl₄ and the Crystal Structure of a Metastable Modification of SeCl₄

Abstract

<jats:title>Abstract</jats:title><jats:p> The system Se-SeCl<jats:sub>4</jats:sub> contains the intermediate phase SeCl which melts incongruently at −48 °C. The tetrachloride is dimorphous with a stable α-and a metastable ß-modification. The crystal structure of ß-SeCl<jats:sub>4</jats:sub> was determined and shown to be an isotype of TeCl<jats:sub>4</jats:sub> with tetrameric cubane-like molecules Se4Cl16.</jats:p>

Taming the Oxidative Power of SeO3 in 1,4-Dioxane, Isolation of Two New Isomers of Mixed-Valence Selenium Oxides, and Two Unprecedented Cyclic Esters of Selenic Acid

“…13 Few colorless crystals identified as β-SeCl 4 were also isolated from the decanted solution after several days, which could be formed only in a reaction of SeO 3 with CCl 4 . 14 The possible subproducts of this reaction are phosgene and CO 2 . However, all our attempts to confirm their presence in the reaction mixture were futile.…”

“…However, it is not possible to eliminate the solvating dioxane molecules even under vacuum; thus, unsolvated Se 3 O 7 should be prepared as reported previously . Few colorless crystals identified as β-SeCl 4 were also isolated from the decanted solution after several days, which could be formed only in a reaction of SeO 3 with CCl 4 . The possible subproducts of this reaction are phosgene and CO 2 .…”

“…Exposing 1 to temperatures over 15 °C or any attempt to recrystallize it led to its decomposition. Raman spectrum: ν̃(int) 109 (33), 128 (46), 135 (39), 177 (59), 204 (43), 278 (33), 331 (31), 393 (15), 408 (25), 473 (31), 594 (6), 716 (5), 826 (53), 849 (10), 876 (6), 926 (100), 987 (34), 994 (80), 1012 (34), 1039 (5), 1089 (6), 1129 (15), 1221 (10), 1298 (6), 1308 (16), 1338 (5), 1376 (5), 1446 (16), 1460 (12), 2670 (2), 2723 (3), 2744 (3), 2782 (3), 2867 (7), 2875 (8), 2900 (10), 2919 (11), 2933 (15), 2948 (12), 2986 (22), 2996 (14), 3013 (17) cm −1 .…”

“…Compound 2 is isolated by filtration and drying in vacuum in 80% yield. Raman spectrum: ν̃(int) 113 (22), 147 (29), 181 (58), 212 (10), 234 (9), 258 (5), 281 (14), 323 (33), 337 (28), 394b (9), 426 (3), 447 (14), 460 (5), 484 (17), 548b (11), 568sh (5), 819 (50), 824 (69), 847 (10), 852 (8), 921 (75), 958 (36), 987 (100), 1011 (30), 1038 (3), 1086 (3), 1125 (13), 1218 (10), 1225 (6), 1295sh (4), 1301sh (5), 1308 (17), 1335 (3), 1374 (5), 1383 (5), 1399 (2), 1443 (19), 1460 (13), 2732 (5), 2737 (6), 2791 (5), 2869 (21), 2895 (20), 2911 (21), 2925 (22), 2971 (21), 2985 (29), 2991sh (26) cm −1 .…”

Sm3O2Sm[SeO3]4 and Sm3O2Cl[SeO3]2: A Monoclinic Form of Samarium Oxide Oxoselenate(IV) and a Samarium Oxide Chloride Oxoselenate(IV) both with 1∞{[O2Sm3]5+} Chains

“…The vertex‐connected [SeCl 6 ] 2– octahedra within the infinite chains 1 ∞ {[SeCl t 4/1 Cl v 2/2 ] – } (t = terminal, v = vertex‐connecting) in [PCl 4 ][SeCl 5 ] behave alike, as they share cis ‐oriented corners, while monomeric [SeCl 5 ] – anions with the expected ψ 1 ‐octahedral shape still remain unknown. Even the tetrameric SeCl 4 (= [Se 4 Cl 4 ]Cl 12 ) with a molecular heterocubane core gives only a slight idea of lone‐pair influence according to {[SeCl 3 ] + (Cl – )} 4 , . With mixed ligands such as oxygen and chlorine in complexes like [SeOCl 3 ] – condensation and lone‐pair activity are found, since dimers [Se 2 O 2 Cl 6 ] 2– with a bridging Cl – ··· Cl – edge of two square [SeOCl 4 ] 2– pyramids with trans ‐oriented oxygen (and lone‐pair) vertices dominate the structure of [As(C 6 H 5 ) 4 ] 2 [Se 2 O 2 Cl 6 ] .…”