The structure of (SCN)(x): a study using molecular and solid-state density functional theory calculations.

Area of Science:

• Polymer Chemistry
• Materials Science
• Computational Chemistry

Background:

• The precise molecular structure of polythiocyanogen ((SCN)x) has been unknown since its initial synthesis in 1929.
• Understanding the polymer's structure is crucial for its potential applications.

Purpose of the Study:

• To elucidate the elusive structure of the (SCN)x polymer.
• To provide strong evidence for the proposed molecular arrangement.

Main Methods:

• Density Functional Theory (DFT) calculations were employed.
• Both molecular and solid-state electronic structure calculations were performed.
• Analysis included energetics and Nuclear Magnetic Resonance (NMR) chemical shifts.

Main Results:

• Calculations indicate the polymer is composed of tangled linear chains.
• The fundamental unit is identified as N-linked S(2)C(2)N five-membered rings.
• A planar chain of 1,2,4-dithiazole rings, with alternating ring orientations, is the most probable local structure.

Conclusions:

• The study provides strong computational evidence for the linear chain structure of (SCN)x.
• The findings resolve a significant structural puzzle in polymer science.
• The proposed structure offers insights into the chemical properties and potential of polythiocyanogen.