JPH03257022A - Compound having structure of cubic type represented by ag7tas6 and its production - Google Patents

Abstract

PURPOSE:To obtain Ag7TaS6 as a compd. useful for a semiconductor, an electronic material, an ionic conductor, etc., by heating a green compact contg. starting material for Ag, starting material for Ta and starting material for S in a prescribed ratio at a prescribed temp. in vacuum. CONSTITUTION:Metallic Ag or Ag2S as starting material for Ag is mixed with Ta or TaS2 as starting material for Ta and S or TaS2 as starting material for S in 7:1:6 atomic ratio of Ag:Ta:S. A green compact of the resulting powdery mixture is put in an alumina crucible and heated at 500-600 deg.C in an evacuated and sealed quartz tube.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to Ag-Ta-5 historical compounds, and particularly to novel compounds useful as semiconductor electronic materials and ion conductors, and methods for producing the same.

(Prior art and problems to be solved) Conventionally, Ag-
In the Ta-8 system, the existence of hexagonal Ag and gTaS2, which are synthesized at temperatures of 900° C. or lower, and rhombohedral Ag1/3 TaS2, which are synthesized at temperatures of 900° C. or lower, are known as ternary compounds.

However, regarding the phase relationship of Ag-Ta-5 system,
There have been almost no reports, and the existence of cubic ternary compounds was completely unknown.

In view of the above circumstances, the present invention aims to provide a technique for obtaining a novel cubic system ternary compound based on Ag-Ta-8.

(Means for Solving the Problem) In order to achieve the above object, the present inventor has developed a novel Ag-Ta-
As a result of repeated research to find 8-series ternary compounds,
Here, we discovered a new compound with a cubic crystal system.

That is, the novel compound according to the present invention has the chemical formula A gt
It is a metal compound having a cubic crystal structure represented by T a S s.

In addition, the manufacturing method uses metallic silver or silver sulfide as a silver raw material, tantalum or tantalum disulfide as a tantalum raw material,
Sulfur, tantalum disulfide or silver sulfide as the sulfur raw material,
Ag, Ta, and S are mixed at an atomic ratio of 7:1:6, the mixed powder is pressed to form a green compact, and this is placed in an alumina crucible and heated in a evacuated quartz sealed tube to 60
It is characterized by heating to a temperature of 0°C.

The present invention will be explained in further detail below.

(Function) The compound represented by the chemical formula Ag7TaS6 according to the present invention is a cubic crystal substance with extremely isotropic cross-contact, in which sulfur is cubically densely packed and metal atoms occupy hexacoordination positions in the gaps. It is.

The lattice constant as a cubic system is a=10.5139±0.0003 (person) V=1162
．． 23f0.09 (3 people), space group F43m (No.
, 216).

The planar index (hkQ), interplanar spacing d (person) (however, do is the measured value, dc is the calculated value) and powder X-ray diffraction intensity I (%) (however, ■. is the measured intensity) for this compound are shown. and,
As shown in Table 1.

[Margin 1 below: Powder X-ray diffraction data of Chikuichio A i-T a Sc This new compound can be produced by the following method.

That is, first, metal silver or silver sulfide as a silver raw material, tantalum or tantalum disulfide as a tantalum raw material, and sulfur, tantalum disulfide, or silver sulfide as a sulfur raw material, Ag
and Ta and S are mixed in an atomic ratio of 7:1:6. This mixed powder was pressurized to form a green compact, which was then placed in an aluminium crucible and placed in a evacuated quartz sealed tube.
This is a method of heating to a temperature of 0°C.

In the case of this method, commercially available starting materials may be used as they are, but if the resulting compound is to be used as a semiconductor electronic material, it is desirable to use one that does not contain impurities and is as pure as possible. In order to promote in-phase chemical reactions during production, the smaller the particle size, the better, and desirably several μm or less.

The raw materials are thoroughly mixed as they are, preferably in an inert gas atmosphere, and then pressure-molded to form a green compact.

Pressurization conditions are not particularly limited, but 1 to 2 tons
A hydrostatic pressure of /cm'' is desirable.

The mixing ratio of the raw materials is such that the atomic ratio of Ag, Ta, and S is 7.
The ratio needs to be 1:6, and if the composition deviates from this ratio, a single phase of the target compound cannot be obtained.

Next, the green compact is placed in an alumina crucible and heated in a evacuated quartz sealed tube at a firing temperature of 500 to 600℃.
It is necessary that the temperature is 00°C.

Although the heating time is not particularly limited, it is preferably 3 to 4 days at 500° C.; heating longer than that is not preferred because tantalum oxide will be produced due to the reaction between the sample and the vessel wall.

After heating, the quartz sealed tube is rapidly cooled in water. The resulting compound powder having the chemical formula Ag7TaS6 is black;
It was found by powder X-ray diffraction that it had a cubic crystal structure.

Next, examples of the present invention will be shown.

(Example) Silver sulfide (Ag, S) powder with a purity of 99.9% or more, tantalum disulfide (TaS2) powder with a purity of 99.96% or more, and sulfur (S) powder with a purity of 99.9999% or more. A, A
The mixture was weighed in a glove box so that the atomic ratio of g, Ta, and S was 7:1:6, mixed in an agate mortar for about 10 minutes, and the mixed powder was pressed to obtain a green compact. .

Next, this was placed in an alumina crucible, vacuum sealed in a transparent quartz tube, placed in a horizontal tubular electric furnace set at 500° C., heated for 4 days, and then the quartz tube was taken out and quenched in water.

The obtained sample was Ag, Tag, single phase, powder
The interplanar spacing d of each reflection was determined by the line diffraction method. and diffraction intensity engineering. The results of the measurements were as shown in Table 1.

Moreover, the lattice constants as a cubic system were as follows.

a=10.5139±0.0003 (person) V=1162
．． 23±0.09C person 3) Surface spacing dc calculated from the above lattice constant and each surface index (hkfi) shown in Table 1
(person) was in extremely good agreement with the actually measured surface spacing d, (person).

(Effects of the Invention) As explained above, according to the present invention, the chemical formula Ag7T
A novel Ag-
It is possible to provide Ta-8 grade compounds, which are particularly useful as semiconductor electronic materials and ion conductors, and have great effects.

Claims (2)

[Claims] (1) A compound having a cubic structure represented by the chemical formula Ag_7TaS_6. (2) Metallic silver or silver sulfide as a silver raw material, tantalum or tantalum disulfide as a tantalum raw material, and sulfur, tantalum disulfide or silver sulfide as a sulfur raw material, Ag, Ta and S
The mixed powder was mixed in an atomic ratio of 7:1:6, and the mixed powder was pressed to form a green compact, which was then placed in an alumina crucible and heated at a temperature of 500 to 600°C in a evacuated quartz sealed tube. 1. A method for producing a compound having a cubic structure represented by Ag_7TaS_6, which comprises heating the compound to .