Two alkali tin­(II) phosphates, namely, Rb­[SnF­(HPO4)] and Rb­(Sn3O)2(PO4)3, were synthesized through mild hydrothermal methods. They belong to the orthorhombic Pnma and Pbcn space groups, respectively. Rb­[SnF­(HPO4)] features a layered structure based on 1D [SnF­(HPO4)]∞ chains interconnected by hydrogen bonds, with Rb+ cations located at the interlayer space. For Rb­(Sn3O)2(PO4)3, each pair of [Sn3O]4+ clusters is bridged by a pair of [P(1)­O4]3– tetrahedra to build a 1D [Sn–P–O]∞ chain. These 1D [Sn–P–O]∞ chains are further cross-linked though [P(2)­O4]3– tetrahedra to construct a 3D network with 7- and 10-membered-ring channels. The tin­(II) ions in Rb­[SnF­(HPO4)] and Rb­(Sn3O)2(PO4)3 with stereochemically active lone pairs (SCALPs) significantly enhance the birefringences of metal phosphates: Δn = 0.147@1064 nm for Rb­[SnF­(HPO4)] and 0.082@1064 nm for Rb­(Sn3O)2(PO4)3.

Upland cotton (Gossypium hirsutum) has long been an important fiber crop, but the narrow genetic diversity of modern G. hirsutum limits the potential for simultaneous improvement of yield and fiber quality. It is an effective approach to broaden the genetic base of G. hirsutum through introgression of novel alleles from G. barbadense with excellent fiber quality. In the present study, an interspecific chromosome segment substitution lines (CSSLs) population was established using G. barbadense cultivar Pima S-7 as the donor parent and G. hirsutum cultivar CCRI35 as the recipient parent. A total of 105 quantitative trait loci (QTL), including 85 QTL for fiber quality and 20 QTL for lint percentage (LP), were identified based on phenotypic data collected from four environments. Among these QTL, 25 stable QTL were detected in two or more environments, including four for LP, eleven for fiber length (FL), three for fiber strength (FS), six for fiber micronaire (FM), and one for fiber elongation (FE). Eleven QTL clusters were observed on nine chromosomes, of which seven QTL clusters harbored stable QTL. Moreover, eleven major QTL for fiber quality were verified through analysis of introgressed segments of the eight superior lines with the best comprehensive phenotypes. A total of 586 putative candidate genes were identified for 25 stable QTL associated with lint percentage and fiber quality through transcriptome analysis. Furthermore, three candidate genes for FL, GH_A08G1681 (GhSCPL40), GH_A12G2328 (GhPBL19), and GH_D02G0370 (GhHSP22.7), and one candidate gene for FM, GH_D05G1346 (GhAPG), were identified through RNA-Seq and qRT-PCR analysis. These results lay the foundation for understanding the molecular regulatory mechanism of fiber development and provide valuable information for marker-assisted selection (MAS) in cotton breeding.

Mild hydrothermal reactions of π-conjugated SC(NH2)2, Ag(NO3), and NaF afforded a new prospective infrared (IR) nonlinear optical (NLO) crystal, namely, Ag[SC(NH2)2]2F. It shows a 3D open framework consisting of corner-sharing AgS4 tetrahedra with six-member ring tunnels that are filled by organic groups of the SC(NH2)2 molecules. Ag[SC(NH2)2]2F maintains 80% transmittance in the spectral region of 0.32–5.91 μm and features large second harmonic generation (SHG) responses with phase-matching at both 1064 nm (15.8 × KH2PO4) and 2.05 μm (0.7 × AgGaS2). It also exhibits a large band gap of 4.19 eV, resulting in a high laser-induced damage threshold (LIDT) of 9.3 times that of AgGaS2. Theoretical calculation revealed that SC(NH2)2, AgS4 tetrahedra, and F– anions all give the positive contribution to SHG effects. Ag[SC(NH2)2]2F overcomes the small band gap and low LIDT of tetrahedral-based chalcogenides while maintaining a large SHG response. This work gives a promising facile design strategy for IR NLO materials.