Syntheses and Characterization of New Mid-Infrared Transparency Compounds: Centric Ba₂BiGaS₅ and Acentric Ba₂BiInS₅

Abstract

Two new mid-infrared transparency compounds, centric Ba(2)BiGaS(5) (1) and acentric Ba(2)BiInS(5) (2), were synthesized from a high-temperature solid-state reaction in evacuated closed silica tubes. Their crystal structures were determined by a single crystal X-ray diffraction method at 293 K. The results of crystal structure solution indicate that compound 1 crystallizes in the centrosymmetric space group Pnma with trans- (1)(∞)[BiGaS(5)](4-) chain structure, while compound 2 crystallizes in the noncentrosymmetric polar space group Cmc2(1) with cis- (1)(∞)[BiInS(5)](4-) chain structure. Two types of lone-pair electrons alignment fashions within (1)(∞)[BiMS(5)](4-) chains result in destructive (for 1) or constructive (for 2) dipole moments, as illustrated in the crystal structures and the partial electron density maps based on the first-principles electronic structure computations. Powder second-harmonic generation (SHG) experiments with a 2.05 μm pumping laser show that the SHG efficiency of the polar compound 2 is approximately 0.8 times that of KTiOPO(4) (KTP) reference. Furthermore, SHG signal intensity measurements using different size particles of powder samples indicate that compound 2 can also achieve type I phase-matching, which makes the compound promising for practical applications.

Synthesis, Crystal Structures, Optical Properties and Theoretical Calculations of Two Metal Chalcogenides Ba2AlSbS5 and Ba2GaBiSe5

“…Among them, many trivalent cations (such as M III ': As, Sb, or Bi) containing chalcogenides have been discovered and shown to have various application prospects. With stereochemically active lone-pair electrons, the above trivalent cations exhibit a flexible coordination environment for the formation of M III 'Q n units (n = 3~6; Q = chalcogen), which offers an opportunity to affect their crystal structures and physicochemical properties [13][14][15][16][17][18][19][20][21][22][23][24]. For example, AAsQ 2 (A = Li, Na; Q = S, Se) [15] and A 3 Ta 2 AsS 11 (A = K, Rb) [13] compounds feature [AsS 3 ] 3-pyramids and show strong second harmonic generation (SHG) responses; BaBiTe 3 , AgBi 3 S 5 and A 2 Bi 8 Se 13 (A = Rb, Cs) compounds exhibit small bandgaps and have promising potential as thermoelectric materials [22][23][24]; Ba 2 GaAsSe 5 shows novel [AsGaSe 5 ] 4− anions and high visible-light-induced photocatalytic reactivity [17].…”

“…Moreover, Ba atoms have flexible coordination numbers (6 to 10) with chalcogens, owing to their large ionic radii, which can also produce distinctive structures in combination with M III 'Q n units. So far, many efforts have been focused on the Ba-M III-M III '-Q system, and several compounds with the Ba 2 M III M III 'Q 5 (M III = Ga, In) formula have been discovered [17][18][19][20][21]. Unfortunately, their structural changes and theoretical calculations have not been systematically studied.…”

Growth and characterization of BaGa4Se7 crystal

“…However, AgGaQ 2 have low laser damage thresholds, whereas ZnGeP 2 exhibits strong two-photon absorption of conventional 1 mm laser (Nd:YAG), which severely limits their applications [4]. Extensive efforts have been made to find new IR NLO materials that could overcome the shortcomings of currently used materials [5][6][7][8][9][10][11][12][13][14][15][16].…”

Syntheses, structures, optical properties, and electronic structures of KBaMSe 3 (M = As, Sb)

“…Since the stereochemical activity of ns 2 lone pair of electrons of group 15 elements M (M = As, Sb, Bi) has profound effects on the crystal structures, electronic structures, and hence on the properties of the resultant compounds, the exploratory synthesis of new group 15 element-containing multinary chalcogenides has been an active area for years and with great efforts many chalcogenides with intriguing structures and properties have been discovered [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][24][25][26][27]. For example, Ba 23-Ga 8 Sb 2 S 38 features an unusual zero-dimensional structure containing totally isolated GaS 4 tetrahedra and discrete SbS 3 pyramids [2]; Bi 3 In 4 S 10 and Bi 14.7 In 11.3 S 38 contain interesting chains of Bi atoms with alternating short Bi-Bi bonds of around 3.1 Å and longer distances of around 4.6 Å [3]; Cs 5 BiP 4 Se 12 [4], Rb 3 Ta 2 AsS 11 [5], La 4 InSbS 9 [6], and Sm 4 GaSbS 9 exhibit very strong second harmonic generation (SHG) responses in the IR range [7].…”