新穎四元硒化合物的合成，結構與物性分析(CrxIn1-x)1.67+2/3δPb4-δIn7Se17、Cu0.8Sn1.4Bi4.8Se9、Ag0.375Sn0.4375Bi2.25Se4

Abstract

在本篇論文中，以固態燒結法合成三種新的化合物。(一)一系列新的 四元化合物(CrxIn1-x)1.67+2/3δPb4-δIn7Se17，在高溫（1023K）下可用固態燒結法 所合成，這一系列四元化合物晶系為monoclinic，空間群為P21/m，其中 Cr1.13Pb3.89In7.61Se17的晶胞常數為a ＝ 13.170(3)□，b ＝ 4.0380(8) □，c ＝ 28.356(6)□，β ＝ 94.54(3)°，V ＝ 1503.3(5)□3，R1/wR2 ＝ 0.0409/0.0998， GOF ＝ 1.075。沿著b軸投影，結構的組成可分為二塊層狀區域，一塊為 [CrInSe2] ∞ 2 -1(CdI2–型），另一塊[Pb ∞ 2 2In4Se6]+4(NaCl(100)–型），此系統化合 物都屬於半導體材料。在室溫下，由反射光譜得知能隙的變化由0.6eV到 1.10eV。此系列化合物的磁性性質，在溫度100K以上皆遵守Curie - Weiss law 有順磁現象且在室溫下由莫耳磁化率可推測Cr原子在化合物中為+3價。 (二)新的四元化合物Cu0.8Sn1.4Bi4.8Se9在高溫(1023K)下可用固態燒結法 合成。Cu0.8Sn1.4Bi4.8Se9:晶系為單斜晶系(monoclinic)，空間群為C2/m，a = 13.703(3)□，b = 4.1830(8)□，c = 15.466(3)□，β = 99.58(3)°，V = 874.2(3) □3，R1/wR2 = 0.0329/0.0768，GOF = 1.070。此結構與Ag0.6Cu0.48Bi6S9為同 結構，由二種不同NaCl–型的區塊所組成，不過目前Cu0.8Sn1.4Bi4.8Se9尚未純 化，所以並沒有進行物理測量。 (三)新的四元化合物Ag0.375Sn0.4375Bi2.25Se4:晶系為hexagonal，空間群為 R m，a = 4.1515(6) □，b = 4.1515(6) □，c = 38.756(8)□，γ = 120°，V = 3578.46(17) □3 ，R1/wR2 = 0.0272/0.0618，與Sn0.571Bi2.286Se4為同結構，具有 層狀結構(Bi2Se3– 型) ， 藉由Thermopower 係數的測量可知 Ag0.375Sn0.4375Bi2.25Se4為n-型半導體。

In this study, three new selenides were synthesized by solid state reactions. (CrxIn1-x)1.67+2/3δPb4-δIn7Se17 crystallizes in monoclinic space group P21/m and Cr1.13Pb3.89In7.61Se17 is a ＝ 13.170(3)□, b ＝ 4.0380(8) □, c ＝ 28.356(6)□, β ＝ 94.54(3)°, V ＝ 1503.3(5)□3, R1/wR2 ＝ 0.0409/0.0998, GOF ＝ 1.075. The structure features the combinations of CdI2 - and NaCl ( 100 ) – types of layer [CrInSe ∞ 2 2]-1 and [Pb ∞ 2 2In4Se6]+4 building units. Electric conductivity and thermopower measurements indicate that these compounds are semiconductors. Room temperature diffuse reflectance spectra absorption experiments for these compounds Show band gaps varies from 0.6 to 1.10 eV. Magnetic susceptibility at T > 100 K for these compounds obey Curie-Weiss law and show paramagnetic behaviors. Magnetic susceptibility data suggests that the oxidation state of Cr is +3. Cu0.8Sn1.4Bi4.8Se9 : it is isostructural with Ag0.6Cu0.48Bi6S9 and crystallizes in monoclinic space group C2/m, a = 13.703(3)□, b = 4.1830(8)□, c = 15.466(3)□, β = 99.58(3)°, V = 874.2(3)□3, R1/wR2=0.0329/0.0768, GOF=1.070. Ag0.375Sn0.4375Bi2.25Se4 : it is isostructural with Sn0.571Bi2.286Se4 and crystallizes in hexagonal space group R m, a = − 3 4.1515(6)□, b = 4.1515(6)□, c = 38.756(8)□, γ = 120°, V = 578.46(17)□3, R1/wR2=0.0272/0.0618, GOF=1.205. The structure of Cu0.8Sn1.4Bi4.8Se9 features combinations of two different blocks( NaCl – type ). This compound can not obtain pure phase, so yet proceeds physic measure. The structure of Ag0.375Sn0.4375Bi2.25Se4 features layer blocks( Bi2Se3 – type ). Thermopower data indicates that Ag0.375Sn0.4375Bi2.25Se4 is a n – type semiconductor and administers to formation of the crystal.