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A cyclic gold(I) trizolate trimer, [Au(3,5-i-Pr2Tz)]3 represents a new class of phosphorescent complexes with a remarkable photophysical behavior, several aspect of which are summarized. This trimer exhibits fully overlapping aurophilically bonded dimer-of-trimer units that lead to multiple phosphorescence bands in both the solid state and solution.

Chalcogenide borates have been developed and are considered an attractive system due to their favorable physical properties such as magnetism and nonlinear optical effects. Here, isostructural RE 6 Nb 2 MgSB 8 O 26 (RE = La-Nd) compounds in the title family have been obtained through cation regulation in rare-earth and VB group metals. This family crystalizes in the centrosymmetric P 3̅ space group and features 3D frameworks formed by {[Mg(NbB 4 O 13 ) 2 ] 16- } ∞ polyanionic layers and QRE 6 octahedra. The structural chemistry was characterized and theoretical calculations were performed to understand the structural merit of this family. In addition, RE 6 Nb 2 MgSB 8 O 26 possess the largest band gaps among known rare-earth chalcogenide borates, and they all show antiferromagnetic-like behaviors.

Novel nonlinear optical (NLO) materials possessing simple chemical compositions and facile syntheses are competitive when considering their practical application. Here, a series of ternary selenides Ga x In 2- x Se 3 ( x = 0.07, 0.38, 0.45, and 0.81) that crystallize in a chiral P 6 5 structure are obtained by melting Ga, In, and Se elements. Their three-dimensional structures are built by (Ga/In)Se 4 tetrahedra and InSe 5 trigonal bipyramids. The hexagonal modification's phase stability is analyzed by energy calculation, and their optical band gaps are determined to be 1.72-1.99 eV. They exhibit large NLO responses that are 1.41-1.64 times that of the benchmark AgGaS 2 . The results of density functional theory calculations suggest that introduction of Ga onto the In site in (InSe 4 ) 5- units can form a deformed tetrahedron with more distortion in the structure, and the (InSe 5 ) 7- units contribute a large amount of birefringence to the structure. This work is the first to investigate the ternary chalcogenides M 2 Q 3 (M = Ga or In; Q = S or Se) as new types of infrared NLO crystals with excellent performances, which will stimulate more interest in those possessing simple compositions and outstanding performances.

New compounds with multiple anions are receiving increasing interest in view of their diverse structures and physical properties. Here we report four isostructural hexanary RE 6 Ta 2 MgQB 8 O 26 (RE = Sm, Eu, Gd; Q = S, Se), belonging to the rare chalcogenide borates. Their structures feature an unprecedented [B 4 O 10 ] 8- unit comprised of one BO 4 and three BO 3 units. Their 3D structures are constructed by the connection between QRE 6 octahedra and the ∞ {[Mg(TaB 4 O 13 ) 2 ] 16- } polyanionic layer. Density functional theory calculations on the electronic structure and a birefringence of 4 are also performed.

Crystallizing in a noncentrosymmetric (NCS) structure is the essential requirement for a crystal to be second-order nonlinear optical (NLO) active. Here, a simple strategy of partial congener substitution is introduced to induce transformation of the known centrosymmetric K 3 Ga 3 Ge 7 Se 20 ( P 2 1 / c ) to the new isostructural NCS species K 3 Ga 3 (Ge 6.17 Sn 0.83 )Se 20 ( 1 ) and K 3 Ga 3 (Ge 4.95 Si 2.05 )Se 20 ( 2 ) ( Pc ). Their structures feature a {[Ga 3 (Ge 7- x M x )Se 20 ] 3- } ∞ (M = Si, Sn) polyanionic framework built from the basic functional motif M'Se 4 (M' = Ga, Ge, M) tetrahedra, similar to but slightly distorted from that of K 3 Ga 3 Ge 7 Se 20 . Their NCS structures are verified by the NLO activities. The NLO response of 1 is ∼1/3 times that of the benchmark AgGaS 2 under a 2.1 μm laser radiation, while 2 exhibits a weak effect, and both are NLO phase-matchable. Their optical band gaps are measured to be 2.02 and 2.12 eV, and they are transparent in the ranges of 0.61-25 and 0.58-25 μm, respectively.

The deficiency of nonlinear-optical (NLO) materials in the IR region inspires strong research interest in this field. Here, Sn 2 Ga 2 S 5 ( 1 ), crystallizing in the orthorhombic Pna 2 1 space group, demonstrates obvious NLO activity, around a maximum of 1.6 times that of AgGaS 2 and a strong laser-induced damage threshold of 9.7 times that of AGS. 1 represents the first NLO-active compound in the M II 2 M III 2 Q 5 (M II = divalent Ca, Sr, Ba, Pb, Sn, and Eu; M III = B, Al, Ga, and In; Q = S and Se) family. The NLO performances of 1 are systematically studied experimentally and theoretically.

Two isostructural adducts CHI 3 ·(S 8 ) 3 (1) and AsI 3 ·(S 8 ) 3 (2) are synthesized by a simple solution method. Both of them crystallize in noncentrosymmetric R3 m, featuring van der Waals interaction linked CHI 3 tetrahedra or SbI 3 trigonal pyramids with crown-like S 8 molecules. Both 1 and 2 show strong SHG responses and phase matchability under either 1.064 or 2.1 μm. The results of DFT calculations indicate that the electron transfer happens from S-3p to I-5p orbitals, and both of them demonstrate indirect band gaps. The NLO effects of 1 and 2 are almost fully contributed from the CHI 3 or AsI 3 units. Compared with AgGaS 2 , their powder laser damage thresholds are ca. 15 and 51 times higher.

Novel Eu 8 In 17.33 S 34 (1) is obtained by a solid state reaction and its structure features three parallel slabs of [In 9.33 S 18 ] ∞ , [Eu 8 ] ∞ , and [In 8 S 16 ] ∞ , together with defects in specific lattice sites. It is the first monoclinic ternary M 8- m In 18- n Q 34 ( M = Pb, Sn, Eu; Q = S, Se) phase member, and the modulation from the ultralong In-S bond and lattice site with strong antibonding effect results in the unique structure feature. Its single crystals show anisotropic conductivity and photoconductivity.

A noncentrosymmetric adduct, SbI 3 ·(S 8 ) 3 , is obtained by a facile solution method. It crystallizes in the trigonal space group R3 m, and its structure features van der Waals force connected, isolated trigonal-pyramidal SbI 3 and chairlike S 8 units. SbI 3 ·(S 8 ) 3 exhibits strong second-harmonic-generation responses around 4 times that of KH 2 PO 4 (1.064 μm) and 1 times that of AgGaS 2 (AGS; 2.1 μm) at 210-250 μm, respectively. Under both laser-radiation wavelengths, it exhibits type I phase-matching behavior. Its laser-induced damage threshold is measured to be around 26 times that of AGS under 1.064 μm. To better understand these optical data, theoretical calculations are performed to address its electronic structure and optical properties.

Reported are the synthesis and structural characterization of a new series of ternary rare-earth mix-chalcogenides RE 4 S 4 Te 3 (RE = Gd, Ho, Er, Tm) that have been obtained from high-temperature solid state reactions. These compounds crystallize in Ho 4 S 4 Te 2.68 structure types with monoclinic C2/ m and/or orthorhombic Immm space groups. The space group variation within this series is due to the position disorder along the Te plane (Te to TeA and TeB). The structural relationship and change between these two space groups are analyzed. It is realized that these compounds are all photocatalytic active under simulated sunlight. The trend of their photocatalytic activities and photocurrent responses is well-explained by using theoretical calculation as well as dipole moment analysis.