Synthesis, Characterization, and Electronic Structure of a New Molybdenum Bronze SnMo₄O₆

Abstract

SnMo4O6 was synthesized at low temperature from the mixture of MoO2 and Mo2O3 using Sn flux. The structure of this compound was determined by the single-crystal X-ray diffraction method. It crystallizes in the tetragonal space group P4/mbm with a = 9.580(4) and c = 2.843(6). The structure of SnMo4O6 is composed of edge-sharing Mo6O12 chains extending down the c axis, and four chains are connected to form channels filled with Sn cations. The resistivity measurement for SnMo4O6 along the chain direction shows that the compound is metallic down to 50 K, and it exhibits semiconducting behavior as the temperature lowers further. It was found from extended Huckel tight-binding band calculation that the compound is likely to be a quasi-one-dimensional metal. The metal−insulator transition in this compound is due to the Fermi surface nesting phenomenon, which originates in the one-dimensional characteristic.

22 New compounds and structures in the solid state

“…88 The template-free material is stable up to 1000 ЊC and its structure was determined by using lattice energy minimization calculations. 20 4 6 ] cage. 90 The first gallium phosphate to contain a 24-ring channel has been prepared.…”

“…The compound is metallic along the chain direction and a semiconductor at lower temperatures. 20 The pair of compounds, CdTeMoO 6 and CoTeMoO 6 , both have simultaneously cation-and anion-deficient 1.1.2 superstructures of fluorite in which the lone pairs of the Te are stereochemically active. 21 Mono-and bi-capped bioctahedral Mo 10 clusters have been found to exist in MTi 0.…”

Microstructure and metal-insulator transition in single crystalline KMo4O6

“…Due to these characteristics of the molybdates, our group has studied the preparation and characterization of many anisotropic molybdenum oxides. In particular, this paper deals with the KMo 4 O 6 phase which is reported to be a quasi-low dimensional system [11][12][13][14][15] . In fact, KMo 4 O 6 can crystallize in two different phases, one is orthorhombic with space group Pbam and another is tetragonal with space group P4 or P4/mbm 12,13 .…”

Comportamento elétrico não convencional no KxMoO2-δ

“…O AMo 4 O 6 (A = Na, K, In, Sn, Li) tem chamado atenção por apresentar transição metal-isolante e possuir estrutura cristalina anisotrópica [19,30- [35] . O SnMo 4 O 6 apresenta comportamento metálico com uma transição metal-isolante próxima de 50 K. Com base nos resultados de resistividade elétrica em função da temperatura para diferentes compostos AMo 4 O 6 , observou-se que a temperatura de transição metalisolante é fortemente dependente do átomo A [19,55]. Para A = K, a transição metal-isolante ocorre em aproximadamente 100 K [19].…”

“…A estrutura cristalina do composto AMo 4 O 6 (à esquerda)[31] e um octaedro com ramificações (Mo 6 O 16 ) onde as letras m, n, q e w indicam as ligações entre Mo-O e as letras d e g as ligações entre Mo-Mo (à direita)[35].Na estrutura do composto AMo 4 O 6 ocorre a formação de canais infinitos de ligações metálicas Mo-Mo ao longo da direção cristalográfica c, como pode ser visualizado no lado esquerdo da figura 1[19,35].Durante a última década tem aumentado o número de pesquisadores interessados em estudar os compostos AMo 4 O 6 (A = K, Sn, Na, Li, Ca, In) devido à transição metal-isolante e a sua anisotropia[19,31,[52][53][54][55].A resistência elétrica em função da temperatura tem sido reportada para o AMo 4 O 6 .Na figura 2 é apresentado o comportamento elétrico do SnMo 4 O 6 . Medida de resistividade elétrica em função da temperatura para o SnMo 4 O 6[19].…”