1312-74-9Relevant academic research and scientific papers
New members of the homologous series Am[M6Se8]m [M5+nSe9+n]: The quaternary phases A1-xM′3-xBi11+xSe20 and A1+xM′3-2xBi7+xSe14 (A = K, Rb, Cs; M′ = Sn, Pb)
Mrotzek,Iordanidis,Kanatzidis
, p. 6204 - 6211 (2001)
The compounds A1+xM′3-2xBi7+xSe14 and A1-xM′3-xBi11+xSe20 (A = K, Rb, Cs; M′ = Sn, Pb) were discovered from reactions involving A2Se, Bi2Se3, M′, and Se at 760 °C. The single-crystal structures reveal that A1+xM′3-2xBi7+xSe14 are isostructural to K2.5Bi8.5Se14 whereas A1-xM′3-xBi11+xSe20 adopt a new structure type. Both compound types belong to the homologous series Am[M6Se8]m [M5+nSe9+n] (M = di- and trivalent metal), whose characteristics are three-dimensional anionic frameworks with tunnels filled with alkali ions. The building units are derived from different sections of the NACI lattice, perpendicular to the [111] (NaCl111-type) and [100] (NaCl100-type) directions, respectively, with dimensions and shapes defined by m and n. The structures of A1+xM′3-2xBi7+xSe14 (m = 2, n = 3) and A1-xM′3-xBi11+xSe20 (m = 1, n = 3) exhibit the same type of stepshaped NACl111-type layer but differ in the size of the NaCl100-type unit. In both structures, the Bi and Sn (Pb) atoms are extensively disordered over the metal sites of the chalcogenide network. The physicochemical and charge transport properties of A1+xM′3-2xBi7+xSe14 and A1-xM′3-xBi11+xSe20 (A = K, Rb, Cs; M′ = Sn, Pb) are reported.
Helical polymer 1/∞[P2Se62-]: Strong second harmonic generation response and phase-change properties of its K and Rb salts
Chung, In,Malliakas, Christos D.,Jang, Joon I.,Canlas, Christian G.,Weliky, David P.,Kanatzidis, Mercouh G.
, p. 14996 - 15006 (2007)
The selenophosphates A2P2Se6 (A = K, Rb) crystallize in the chiral trigonal space group P3121, with a = 7.2728(9) A, c = 18.872(4) A, and Z = 3 at 298(2) K and a = 14.4916(7) A, c = 18.7999(17) A, and Z = 12 at 173(2) K for K + salt and a = 7.2982(5) A, c = 19.0019(16) A, and Z = 3 at 100(2) K for Rb+ salt. The A2P2Se 6 feature parallel one-dimensional helical chains of 1/∞[P 2Se62-] which depict an oxidative polymerization of the ethane-like [P2Se6]4- anion. On cooling well below room temperature K2P2Se 6 exhibits a displacive phase transition to a crystallographic subgroup and forms a superstructure with a cell doubling along the a- and b-axes. The Rb analogue does not exhibit the phase transition. The compounds are air stable and show reversible glass-crystal phase-change behavior with a band gap red shift of 0.11 and 0.22 eV for K+ and Rb+ salts, respectively. Raman spectroscopy, 31P magic angle spinning solid-state NMR, and pair distribution function (PDF) analysis for crystalline and glassy K2P2Se6 give further understanding of the phase transition and the local structure of the amorphous state. K 2P2Se6 exhibits excellent mid-IR transparency and a strong second harmonic generation (SHG) response. The SHG response is type-I phase-matchable and in the wavelength range of 1000-2000 nm was measured to be 50 times larger than that of the commercially used material AgGaSe 2. Glassy K2P2Se6 also exhibits an SHG response without the application of electric field poling. In connection with the NLO properties the thermal expansion coefficients for K 2P2Se6 are reported.
APdCu(Se2)(Se3) (A = K and Rb): New quaternary copper palladium polyselenides with unusual metal-selenium coordination
Chen, Xuean,Dilks, Kieran J.,Huang, Xiaoying,Li, Jing
, p. 3723 - 3727 (2003)
Two novel metal polyselenides, KPdCu(Se2)(Se3) (I) and RbPdCu(Se2)(Se3) (II), have been synthesized from solvothermal reactions in superheated ethylenediamine at 160 °C. The isostructural compounds crystallize in the monoclinic space group P21/m, Z = 2, with a = 6.145(1) A, b = 7.268(1) A, c = 8.865(2) A, β = 102.41(3)° for I, and a = 6.253(1) A, b = 7.267(1) A, c = 8.993(2) A, β = 102.28(3)° for II. Their crystal structures are two-dimensional networks with ∞2[PdCu(Se2) (Se3)]- anionic layers built from one-dimensional ∞1[Pd(Se2) (Se3)]2- chains that are stitched together by tetrahedrally coordinated Cu atoms. The DSC data show that I and II are stable up to 400 °C and decompose at ca. 436 and 424 °C, respectively. Both compounds are narrow band-gap semiconductors with estimated band gaps of about 0.7 eV (I) and 0.8 eV (II), respectively. They are the first structurally characterized quaternary copper palladium polychalcogenides with a (Se2)2- and a (Se3)2- fragment, both exhibiting interesting and unusual metal-selenium coordination.
Photochemical production of F centers in KBr crystals doped with Se2-
Cook,Dryden,Gwan,Ferguson
, p. 415 - 418 (1987)
The photochemical production of F centers in KBr.Se2- crystals has been investigated using crystals doped by a method different to that used by others. The formation of F centers is a complicated process and depends on the intensity of irradiating light, temperature and wavelength. Low-power irradiation favors F center formation by ionization of free Se2- in freshly quenched crystals. Low-temperature UV laser irradiation forms both normal F centers and one other center with an absorption band very close to the normal F center. The nature of this second center is not known.
Tropochemical Cell-Twinning in the New Quaternary Bismuth Selenides K xSn6-2xBi2+xSe9 and KSn 5Bi5Se13
Mrotzek, Antje,Kanatzidis, Mercouri G.
, p. 7200 - 7206 (2003)
The quaternary KxSn6-2xBi2+xSe 9 were discovered from reactions involving K2Se, Bi 2Se3, Sn, and Se. The single crystal structures reveal that KxSn6-2xBi2+xSe9 is isostructural to the mineral heyrovskyite, Pb6Bi2S 9, crystallizing in the space group Cmcm with a = 4.2096(4) A, b = 14.006(1) A, and c = 32.451(3) A while KSn5Bi 5Se13 adopts a novel monoclinic structure type (C2/m, a = 13.879(4) A, b = 4.205(1) A, c = 23.363(6) A, β = 99.012(4)°). These compounds formally belong to the lillianite homologous series xPbS·Bi2S3, whose characteristic is derivation of the structure by tropochemical cell-twinning on the (311) plane of the NaCl-type lattice with a mirror as twin operation. The structures of KxSn6-2xBi2+xSe9 and KSn 5Bi5Se13 differ in the width of the NaCl-type slabs that form the three-dimensional arrangement. While cell-twinning of 7 octahedra wide slabs results in the heyrovskyite structure, 4 and 5 octahedra wide slabs alternate in the structure of KSn5Bi5Se 13. In both structures, the Bi and Sn atoms are extensively disordered over the metal sites. Some physicochemical properties of K xSn6-2xBi2+xSe9 and KSn 5Bi5Se13 are reported.
Syntheses, structures, optical properties, and electronic structures of KBaMSe3(M = As, Sb)
Yin, Wenlong,Feng, Kai,Kang, Lei,Kang, Bin,Deng, Jianguo,Lin, Zheshuai,Yao, Jiyong,Wu, Yicheng
, p. 287 - 291 (2014)
The first two members in the quaternary A/A′/M/Q (A = alkali metal; A′ = alkaline-earth metal; M = As, Sb, Bi; Q = S, Se, Te) system, namely the KBaMSe3(M = As, Sb) selenides, have been synthesized by solid state reactions. They are isostructural and crystallize in the centrosymmetric space group P21/c of the monoclinic system. In the structure, the trivalent M atom (M = As, Sb) is coordinated to three Se atoms forming a trigonal pyramid with the Se atoms serving as the triangle base, showing the stereochemical activity of the ns2lone pair electron. The MSe3(M = As, Sb) trigonal pyramids are totally isolated from each other with K+and Ba2+cations located between them. The optical band gaps of 2.26 (2) eV for KBaAsSe3and 2.04 (2) eV for KBaSbSe3, were deduced from the diffuse reflectance spectra. The first principles calculations were performed to study the electronic structures of KBaMSe3(M = As, Sb) compounds and the results indicated that these two compounds are indirect band gap semiconductors.
The noncentrosymmetric chain compounds, A3M2AsSe 11 (A = K, Rb, Cs; M = Nb, Ta)
Do, Junghwan,Kanatzidis, Mercouri G.
, p. 41 - 49 (2004)
The noncentrosymmetric niobium and tantalum selenoarsenates, A 3Nb2AsSe11 (A=K, Rb, Cs) and K 3Ta2AsSe11, were synthesized in a polyselenoarsenate flux. All compounds crystallize in the polar monoclinic space group Cc. The structures are comprised of the same type of infinite chain anions, [M2Se2(Se2)3(AsSe 3)]3- (M=Nb, Ta) separated by alkali metal cations. The As3+ centers with nonbonded electron pairs play an important role in stabilizing the noncentrosymmetric structures. UV-Vis spectroscopy, Raman spectroscopy and differential thermal analysis data are reported. The energy gaps of these compounds vary between 1.35 and 1.53eV.
K2Sn2ZnSe6, Na2Ge2ZnSe6, and Na2In2GeSe6: A new series of quaternary selenides with intriguing structural diversity and nonlinear optical properties
Zhou, Molin,Li, Chao,Li, Xiaoshuang,Yao, Jiyong,Wu, Yicheng
, p. 7627 - 7633 (2016)
Three new compounds (i.e., K2Sn2ZnSe6, Na2Ge2ZnSe6, and Na2In2GeSe6) with intriguing structural diversity and nonlinear optical properties were discovered for the first time. They crystallize in space groups P4/ncc, I4/mcm and Cc, respectively. In K2Sn2ZnSe6 and Na2Ge2ZnSe6, the [Sn(Ge)Se4] tetrahedra and [ZnSe4] tetrahedra are linked via edge-sharing to build up a 1D [Sn2ZnSe6] infinite chain separated by K+(Na+) cations along the c direction, while the structure of Na2In2GeSe6 is an interesting three-dimensional framework composed of [InSe4] and [GeSe4] tetrahedra via corner-sharing with Na+ cations in the cavities. The experimental optical band gaps of these compounds were determined as 1.71(2) eV, 2.36(4) eV and 2.47(2) eV, respectively, according to UV-vis-NIR diffuse reflectance spectroscopy. Interestingly, in addition to the large band gap (1.80 eV for AgGaSe2, as a comparison), Na2In2GeSe6 exhibits phase-matchable nonlinear optical (NLO) properties with a powder second harmonic generation signal about 0.8 times that of AgGaS2. Moreover, Na2In2GeSe6 melts congruently at a rather low temperature of 671 °C, which suggests that bulk crystals can be easily obtained by the Bridgman-Stockbarger method. Our preliminary results indicate that Na2In2GeSe6 has promising applications in IR nonlinear optics.
Na2GaS2Cl: A new sodium-rich chalcohalide with two-dimensional [GaS2]∞layers and wide interlayer space
Li, Xiaoshuang,Liang, Fei,Liu, Tianpeng,Li, Haifeng
, p. 11167 - 11172 (2021)
By introducing halogens to the A/Ga/Q (A = Na, K; Q = S, Se) system, one new chalcohalide namely Na2GaS2Cl was successfully obtained. It crystallizes in the orthorhombic space group Cmcm (63). Na2GaS2Cl has a layered structure consisting of two dimensional [GaS2]∞ layers which are stacked in face to face and back to back arrays and separated by Na+ and Cl- ions. Interestingly, supertetrahedral building units [Ga4S10] (T2) which are rarely found in metal chalcogenides and metal chalcohalides are formed in this structure. Moreover, the distances of two adjacent layers are around four times larger than the ionic radius of the Na+ ion, which is very likely to provide a perfect environment for the storage and migration of Na+ ions. In particular, the volume concentration of the Na+ cations in this compound is as high as 1.54 × 1022 cm-3. The UV-vis-NIR spectroscopy measurement reveals that the optical band gap of this title compound is 3.06 eV. The electronic structural calculations on Na2GaS2Cl show that the band gap is mainly determined by the [GaS4] groups and Na-Cl ionic bonding.
Layered and Cubic Semiconductors AGa M′ Q4(A+= K+, Rb+, Cs+, Tl+M′4+= Ge4+, Sn4+Q2-= S2-, Se2-) and High Third-Harmonic Generation
Friedrich, Daniel,Byun, Hye Ryung,Hao, Shiqiang,Patel, Shane,Wolverton, Chris,Jang, Joon Ik,Kanatzidis, Mercouri G.
, p. 17730 - 17742 (2020)
Eighteen new quaternary chalcogenides AGaM′Q4 (A+ = K+, Rb+, Cs+, Tl+ M′4+ = Ge4+, Sn4+ Q2- = S2-, Se2-) have been prepared by solid-state syntheses and structurally characterized using single-crystal X-ray diffraction techniques. These new phases crystallize in a variety of layered structure types. The tin analogues also adopt an extended three-dimensional network structure as polymorphs. The polymorphism and phase-stability in these cases were studied by thermal analysis and high-temperature in situ X-ray powder diffraction. All compounds are semiconductors with the colored selenides absorbing light in the infrared-green region (1.8 eV a large band gap and shows stability under ambient conditions with no significant irradiation damage.
