In the course of our structural investigations of borates synthesized under high-pressure, high-temperature conditions, we discovered several new high-pressure modifications [1][2][3][4][5] with interesting structural features and physical properties, for example, a new non-centrosymmetric modification of bismuth triborate (d-BiB 3 O 6 ).[6] Along with the investigation of these phase transitions, we aim to synthesize borates with new compositions, whose existence is presumably based on high-pressure conditions during synthesis. Examples are the borates RE 3 B 5 O 12 (RE = Tm-Lu), [7] RE 4 B 6 O 15 (RE = Dy, Ho), [8][9][10] a-RE 2 B 4 O 9 (RE = SmHo), [11][12][13] b-RE 2 B 4 O 9 (RE = Gd, Dy), [14,15] and Pr 4 B 10 O 21 , [16] which have no corresponding ambient-pressure modifications. To our surprise, the borates RE 4 B 6 O 15 (RE = Dy, Ho) [8][9][10] revealed edge-sharing as well as corner-sharing BO 4 tetrahedra; such edge-sharing tetrahedra had been previously unknown in the varied structural chemistry of borates. Later on, we discovered a second type of structure, a-RE 2 B 4 O 9 (RE = Sm-Ho), [11][12][13] that also display this new structural feature. Herein, we report the synthesis and characterization of a new nickel borate HP-NiB 2 O 4 , in which each BO 4 tetrahedron shares a common edge with a second BO 4 tetrahedron.In the system NiO-B 2 O 3 , there is only one nickel borate, of the composition Ni 3 (BO 3 ) 2 . [17][18][19][20] This compound displays trigonally coordinated boron atoms and Ni 2+ ions with octahedral coordination. Recently, Pompetzki and Albert found a new synthetic route to pure Ni 3 (BO 3 ) 2 ; they employed the thermal decomposition of a mixture of NiCO 3 ·2 Ni(OH) 2 ·4 H 2 O and H 3 BO 3 .[21] In our own investigations of the Ni-B-O ternary system, we synthesized a second borate of the composition b-NiB 4 O 7[22] under high-pressure conditions of 7.5 GPa and at a temperature of 1000 8C; this compound has a structure analogous to the high-pressure modification b-ZnB 4 O 7 .[5] With HP-NiB 2 O 4 , we have now found a third composition in the Ni-B-O ternary system, which accentuates the performance of high-pressure synthesis in solid-state chemistry.HP-NiB 2 O 4 was synthesized in a high-pressure, hightemperature reaction at 7.5 GPa and 680 8C in a modified Walker module (multianvil assembly) starting from the oxides NiO and B 2 O 3 [Eq.(1)]. [23] NiO þ B 2 O 3 !HP-NiB 2 O 4 ð1Þ

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[11][12][13] b-RE 2 B 4 O 9 (RE = Gd, Dy) [14,15] und Pr 4 B 10 O 21 , [16] für die bisher keine entsprechenden Normaldruckmodifikationen bekannt sind. Zu unserer Überra-schung zeigten die Borate RE 4 B 6 O 15 (RE = Dy, Ho) [8][9][10] neben eckenverknüpften BO 4 -Tetraedern erstmals das Strukturmotiv kantenverknüpfter BO 4 -Tetraeder, das bis dahin in der variantenreichen Strukturchemie der Borate fehlte. Im Verlauf unserer Arbeiten entdeckten wir einen zweiten Strukturtyp, a-RE 2 B 4 O 9 (RE = Sm-Ho), [11][12][13] der ebenfalls dieses neue Strukturmotiv aufweist. Hier berichten wir nun erstmals über die Synthese und Charakterisierung eines

Two tetraalkoxy‐λ4‐telluranes were prepared from tellurium tetrachloride and the sodium salts of methanol and 2,2,2‐trifluoroethanol, respectively. Their molecular structures which were determined by single‐crystal X‐ray diffraction show dipolar intermolecular contacts. NBO analyses for the title compounds were conducted to assess the role of the stereochemically active lone pair on the tellurium atoms.

Methylenebisarsonic acid (3) was synthesized according to a published procedure. Its molecular structure and its spectroscopic characteristics were determined by single-crystal X-ray diffraction. The first intermediate, methylenebis(dichloroarsane) (1), was structurally and spectroscopically characterized as well. Both