JPH0242769B2 - - Google Patents

Description

[Detailed description of the invention]

Industrial Application Field The present invention is a novel compound having the general formula M _X Ti _16-X
Ga _16+X O ₅₆ (M is one or more alkali metals selected from K, Rb and Cs, x=
Represents 0.1 to 2.0. The present invention relates to a compound having a tetragonal tunnel structure represented by (the same applies hereinafter) and a method for producing the same. The new compounds are useful as cation conductors, ion exchangers, catalysts, heat resistant materials, and heat insulating materials. OBJECT OF THE INVENTION An object of the present invention is to provide a useful new compound as described above and a method for producing the same. Structure of the invention The novel compound of the present invention has the general formula M _X Ti _16-X Ga _16+X
In the compound represented by O ₅₆ , Ti ⁴⁺ has TiO ₆ octahedral coordination, but Ga ³⁺ has both CaO ₆ octahedral and GaO ₄ tetrahedral coordination, and these chains form 4 octahedrons. It is a compound characterized by having a large tunnel structure formed by sharing four vertices of a _tetrahedron .
By replacing X octahedrons with trivalent GaO ₆ octahedrons, X M atoms (representing the same as above) are coordinated in the tunnel in order to adjust the cation charge. To explain this based on the drawings, as shown in Fig. 1a, it belongs to the tetragonal crystal system and has a tunnel structure with a large diameter. All tetrahedra are GaO ₄ ,
The octahedrons that form the framework of the large-diameter tunnel are composed of TiO ₆ and GaO ₆ , which are randomly distributed at a ratio of 30% and 70%, respectively.
The octahedrons forming the rutile structural unit as shown in Figure 1b are all _TiO6- coordinated, and the octahedra forming the β-gallium structural unit as shown in Figure 1c are all _GaO6- coordinated. be. Planar index (hk1), interplanar spacing (d (Å)) of this crystal (composition of K _0.8 Ti _5.2 Ga _16.8 O ₅₆ ) (d _pbs is actual measurement, d _calc is calculated value), relative reflection intensity for X-rays I (%)
is shown in Table 1.

【table】

[Table] The space group is I4/m and belongs to the tetragonal system. The lattice constants differ depending on the composition, but in the case of K _0.8 Ti _15.2 Ga _16.8 O ₅₆ , a = 18.135 (Å), C = 2.9966 (Å), the unit volume is V = 985.5 (Å ³ ), and the number of molecules is 1 in the unit cell. The measured density is 4.69 g/cm ³ . The crystal habit is acicular to fibrous. Methods for producing the compound of the present invention include a flux method and a calcination method. The flux method yields needle-shaped crystals, while the sintering method yields powder crystals. (1) In the flux method, an alkali metal oxide selected from K ₂ O, Rb ₂ O, and Cs ₂ O or a compound decomposed into the alkali metal oxide by heating, and titanium oxide or a compound that is decomposed into the alkali metal oxide by heating. A compound that decomposes into titanium oxide and a compound that decomposes into gallium oxide by heating are expressed by the general formula (M ₂ O) _X (TiO ₂ ) _Y (Ga ₂ O ₃ ) _Z (where M is K, One or more alkali metals selected from Rb and Cs, X and Y are 0.1 to 2.0,
A mixture of molybdenum oxide or a compound decomposed into molybdenum oxide by heating, and an alkali metal oxide selected from K, Rb, and Cs are used as crystal raw materials. Alternatively, a compound that is decomposed into the alkali metal oxide by heating has the general formula M ₂ O・n (MoO ₃ ), where M is K,
Rb or Cs (n = 1 to 2) is used as a flux raw material, and the crystal raw material and flux raw material are mixed in a molar percentage of 30:70 to 10:90. death,
This is a method of growing a single crystal by heating and melting the mixture at 1200 to 1400°C and slowly cooling the melt to 900 to 1000°C. The slow cooling temperature is 1℃/h ~ 100℃
C/h may be sufficient, but in order to obtain long needle-like crystals of good quality, a rate of 2° C./h to 10° C./h is appropriate. This method yields acicular crystals, which are suitable for ionic conductors and heat-resistant/insulating materials. (2) In the production method using the calcination method, an alkali metal oxide selected from K ₂ O, Rb ₂ O, and Cs ₂ O or a compound decomposed into the alkali metal oxide by heating, and titanium oxide or heating A compound decomposed into titanium oxide by gallium oxide or a compound decomposed into gallium oxide by heating is expressed by the general formula M _X Ti _16-X Ga _16+X O ₅₆ (where M is K,
(Represents Rb or Cs, x = 0.1 to 2.0)
Mix the mixture to the composition ratio shown in 1000
This method involves firing at a temperature of ℃ or higher. According to this method, a powdery crystalline material is obtained, which is suitable for ion exchangers, catalysts, and heat-resistant and heat-insulating materials in the form of sintered bodies. When using this method, it is desirable to use fine particles as the raw material powder in order to promote the chemical reaction. In addition, examples of compounds that generate each raw material metal oxide upon heating include carbonates, bicarbonates, hydroxides, nitrates, halides, and oxyhalides of each raw material metal. Example 1 Potassium carbonate powder, titanium oxide powder, and gallium oxide powder of 99.9% or more were mixed into (K ₂ O) _0.7 (TiO ₂ ) _1.0
(Ga ₂ O ₃ ) 20 mol of crystal raw material mixed at a composition ratio of _0.5
%, potassium carbonate powder, molybdenum powder,
(K ₂ O) (MoO ₃ ) 80 mol% of the flux raw material mixed at a composition ratio of _1.5 was mixed. This mixture 123
Put g into a 100ml platinum crucible and melt at 1300℃,
After holding for 10 hours, it was slowly cooled to 1000°C at a rate of 4°C/h. After slow cooling, the crucible was left to cool in the air to cool to room temperature. The crucible was immersed in boiling water to dissolve the flux and separate the crystals. The obtained crystals were an aggregate of needle-like crystals with a length of 10 mm. Identification by X-ray diffraction showed the crystallographic properties shown in Table 1 above. Examples 2 and 3 In place of K ₂ CO ₃ in Example 1, each
Rb ₂ CO ₃ and CsCO ₃ were used. All Example 1
Acicular crystals with the same crystal structure as in were obtained. Example 4 Using the crystal raw material used in Example 1, (K ₂ O) _1
/2 (TiO ₆ ) _15.0 (Ga ₂ O ₃ ) _17/2 . Approximately 10 g of the well-mixed mixture was calcined at 1200°C for 1 hour in a 30 ml platinum crucible, and then ground and mixed. It was fired again at 1200°C for 15 hours. The result of X-ray diffraction of the obtained powder showed the crystallographic properties shown in Table 1 above. Examples 5 and 6 The same results as in Example 4 were obtained when Rb ₂ O and Cs ₂ O were used in place of K ₂ O in Example 4. Effects of the Invention The present invention has the excellent effect of providing a new compound useful as a cation conductor, ion exchanger, catalyst, and heat-resistant heat insulating material.

[Brief explanation of the drawing]

FIG. 1 is a diagram of the crystal structure of the compound of the present invention, in which a shows the crystal structure, b shows the coordination of TiO ₆ , and c shows the coordination of GaO ₆ .

Claims (1)

[Claims] 1. General formula M _X Ti _16-X Ga _16+X O ₅₆ (where M is K,
A compound having a tetragonal tunnel structure represented by one or more alkali metals selected from Rb and Cs, x = 0.1 to 2.0. 2. An alkali metal oxide selected from K ₂ O, Rb ₂ O and Cs ₂ O or a compound decomposed into the alkali metal oxide by heating, and titanium oxide or a compound decomposed into titanium oxide by heating,
Gallium oxide or a compound that is decomposed into gallium oxide by heating is expressed by the general formula (M ₂ O) _Y (TiO ₂ ).
_Z (Ga ₂ O ₃ ) _Z/2 (M is one or more alkali metals selected from K, Rb and Cs,
A mixture of molybdenum oxide or a compound decomposed into molybdenum oxide by heating and an alkali metal selected from K, Rb, and Cs is used as the crystal raw material. The oxide or the compound decomposed into the alkali metal oxide by heating has the general formula M ₂ O・n (MoO ₃ ) (where M is K,
Rb, or Cs, n = 1 to 2) is used as a flux raw material, and the crystal raw material and flux raw material are mixed at a molar percentage of 30.
The mixture was heated and melted at 1200 to 1400°C, and the melt was heated to 900°C.
_A tetragonal crystal _system represented _{by M} A method for producing a compound having a tunnel structure. 3 An alkali metal oxide selected from K ₂ O, Rb ₂ O and Cs ₂ O or a compound decomposed into the alkali metal oxide by heating, titanium oxide or a compound decomposed into titanium oxide by heating, Gallium or a compound that decomposes into gallium oxide by heating is expressed by the general formula M _X Ti _16-X Ga _16+X O ₅₆
(However, M represents K, Rb or Cs, and X=0.1
~2.0) is mixed to the composition ratio indicated by
A tetragonal tunnel structure represented by the general formula M _X Ti _16-X Ga _16+X O ₅₆ (where M and A method for producing a compound having