During the last decades, layered structures have attracted particular and increasing interest due to the multitude of outstanding properties exhibited by their representatives. Particularly common among their archetypes, with a significant number of mineral and synthetic species structural derivatives, is that of litharge. In the current paper, we report the structural studies of two later rare-earth oxysulfates, [Ln₂O₂]SO₄ (Ln = Dy, Ho), which belong indeed to the grandreefite family, and a novel compound [Bi₂CuO₃]SO₄, which belongs to a new structure type and demonstrates the second example of Cu²⁺ incorporation into litharge-type slabs. Crystals of [Bi₂CuO₃]SO₄ were obtained under high-pressure/high-temperature (HP/HT) conditions, whereas polycrystalline samples of [Ln₂O₂]SO₄ (Ln = Dy, Ho) compounds were prepared via an exchange solid-state reaction. The crystal structure of [Bi₂CuO₃]SO₄ is based on alternation of continuous [Bi₂CuO₃]²⁺ layers of edge-sharing OBi₂Cu₂ and OBi₃Cu tetrahedra and sheets of sulfate groups. Cu²⁺ cations are in cis position in O5Bi₂Cu₂ and O6Bi₂Cu₂ oxocentered tetrahedra in litharge slab. The crystal structure of [Ln₂O₂]SO₄ (Ln = Dy, Ho) is completely analogous to those of grandreefite and oxysulfates of La, Sm, Eu, and Bi.

In the article some results of a theoretical study of the structure and conformational dynamics of cyclopropanoic acid fluoride (C₃H₅CFO) and cyclopropanoic acid chloride (C₃H₅CClO) molecules are presented. The geometrical structure of conformers, their relative energies, barriers to internal rotation, and transition energies in the low-frequency region of the vibrational spectrum are calculated. The effect features of the potential energy surface and the behavior of kinematic factors have on the torsion frequency values is discussed. The possible kinematic interaction between the internal rotation and out-of-plane deformation vibration of the formyl group is studied.

NOPT is an ab initio package for calculations using Non-Orthogonal methods and multireference Perturbation Theory. It can be used both as a ready-to-use quantum chemistry program and as an open-source system for modifying existing methods and developing new ones. The key functionality includes restricted Hartree–Fock, configuration interaction with single excitations, complete active space self-consistent field, and several multireference perturbation theory (MRPT) methods. The MRPT module provides extended multiconfigurational quasi-degenerate perturbation theory (XMCQDPT2), multipartitioning perturbation theory (MPPT2), and a novel variant of uncontracted MRPT—CDAS-PT2. NOPT allows one to perform a complete computational workflow starting from a molecular geometry. It also contains an interface for using data calculated by other quantum chemistry programs. The implemented non-orthogonal methods are aimed at the fragment-based calculations with multireference wave functions. All the methods are implemented with the resolution of identity approximation to gain higher performance. We hope that this makes NOPT a useful tool for the calculations with both standard and novel methods of quantum chemistry.