Amorphous precursors for low-temperature preparation of chevrel phases M{sub x}Mo{sub 6}S{sub 8} and their tungsten analogues

Journal Article · Sat Jul 01 04:00:00 EDT 1995 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1006/jssc.1995.1273· OSTI ID:149622

McCarley, R E; Hilsenbeck, S J; Xie, X ^[1]

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1. Iowa State Univ., Ames, IA (United States)

High-yield preparations of the amorphous ternary salts Na{sub 2x}(Mo{sup 6}S{sub 8})S{sub x}{center_dot} yMeOh (with x = 1.0 to 1.5, y = 4 to 5) and Na{sub 2.1} (W{sub 6}S{sub 8})S{sub 1.05} {center_dot}5.4MeOH have been devised by reaction of M{sub 6}Cl{sub 12} (M = Mo or W) with NaSH and NaOBu in various ratios in refluxing n-BuOH for M = Mo and in refluxing MeCN for M = W. Characterization of these amorphous materials by chemical and spectroscopic methods (IR, Raman, PES) shows that the (M{sub 6}S{sub 8}){sup 0} cluster units are present. Vacuum thermolysis of the amorphous Na{sub 2x}(Mo{sub 6}S{sub 8})S{sub x} {center_dot}yMeOH first produces poorly crystalline NaMo{sub 6}S{sub 8} by disproportionation at 800{degrees}C and well-crystallized NaMo{sub 6}S{sub 8} at {ge}900{degrees}C. The amorphous tungsten compound disproportionates to W and WS{sub 2} at {ge}200{degrees}C. Ion exchange of the sodium material in methanol with soluble M{sup 2+} and M{sup 3+} salts (M = Sn, Co, Ni, Pb, La, Ho) produces the Mn{sup +}{sub 2x/n}(Mo{sub 6}S{sub 8})S{sub x} {center_dot}yMeOH compounds. For tungsten, only exhcange with SnCl{sub 2} in THF was examined and resulted in Sn{sub x}(W{sub 6}S{sub 8})S{sub x} {center_dot}yMeOH. Conversion of Sn{sub x}(Mo{sub 6}S{sub 8})S{sub x} {center_dot}yMeOH to poorly crystalline Chevrel phase, SNMo{sub 6}S{sub 8}, was achieved by reduction under H{sub 2} at 600{degrees}C. Well-crystallized SnMo{sub 6}S{sub 8} resulted at high temperatures. Conversion of Sn{sub x}(W{sub 6}S{sub 8})S{sub x}{center_dot}yMeOH to SnW{sub 6}S{sub 8} was not successful.

• OSTI ID: 149622
• Journal Information: Journal of Solid State Chemistry, Journal Name: Journal of Solid State Chemistry Journal Issue: 2 Vol. 117; ISSN 0022-4596; ISSN JSSCBI
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ABSORPTION SPECTROSCOPY
CHEMICAL PREPARATION
COBALT SULFIDES
HOLMIUM SULFIDES
LANTHANUM SULFIDES
LEAD SULFIDES
NICKEL SULFIDES
OXIDATION
REDUCTION
SODIUM SULFIDES
TIN SULFIDES
TUNGSTEN SULFIDES