The crystal structure and optical activity of potassium dithionate,

Abstract

The absolute chirality of potassium dithionate, K 2 S 2 O 6 , M r = 238.3, trigonal, space group P 321, a = 9.782(1) Å, c = 6.298(2) Å, V = 521.9(1) Å3 , Z = 3, R = 0.024, wR = 0.031 for 2586 unique observed reflections, has been determined at room temperature through a combination of single-crystal x-ray diffraction, including anomalous scattering, and optical study. Using a classical point dipole-dipole theory, good agreement has been obtained between the calculated and observed optical activity and refractive indices at room temperature (ρ = −6.57 • mm −1 along [001], n e = 1.512, n 0 = 1.453 at a wavelength of 632.8 nm). The polarizabilities of the different atoms have also been determined by means of this theory. It has been found that in order to fit the optical data, it is necessary that the oxygen atoms must show quite large anisotropic polarizabilities. The structural features responsible for the optical rotation have been identified. In this way, a visual correlation between the sign of the optical activity and the arrangement of atoms in the crystal structure has been established.

Experimental and phenomenological aspects of circular birefringence and related properties in transparent crystals

“…Table A.12. Absolute structure of laevorotatory K 2 S 2 O 6 P 32 1 (Gomes, Ortega, Etxebarria, Zuniga and Breczewski 1996). a = 9.782 Å, c = 6.298 Å.…”

“…This rule is conserved in centrosymmetric incommensurate phases where previously reported effects are of a parasitic nature. (Gomes, Ortega, Etxebarria, Zuniga and Breczewski 1996). a = 9.782 Å, c = 6.298 Å.…”

Visualizing the Dose Distribution and Linear Energy Transfer by 1D and 2D ESR Imaging: A Potassium Dithionate Dosimeter Irradiated with C6+ and N7+ Ions

“…6 In recent years, ESR dosimetry based on dithionates ((NH 4 ) 2 S 2 O 6 , BaS 2 O 6 , Li 2 S 2 O 6 , and K 2 S 2 O 6 ) has emerged as an attractive alternative to L-alanine ESR dosimetry when deviations from tissue-equivalence can be tolerated. 8,13 Radiotherapy is currently based mostly on irradiation with photons and electrons. However, irradiation by protons and heavy ions is studied with great interest and is expected to be more frequently used in the future, because of its ability to locally confine the radiation and to protect the surrounding tissue.…”

“…In recent years, ESR dosimetry based on dithionates ((NH 4 ) 2 S 2 O 6 , BaS 2 O 6 , Li 2 S 2 O 6 , and K 2 S 2 O 6 ) has emerged as an attractive alternative to l -alanine ESR dosimetry when deviations from tissue-equivalence can be tolerated. – The ESR spectrum in the irradiated dithionates consists of a superposition of two isotropic signals with no hyperfine splittings and slightly different g values. The signals were assigned to two •SO 3 − radicals in different local environments in terms of spin−lattice interactions, thus leading to different g values and relaxation times. , …”

Pb2[C2O6]-P3̄m1: new insights into the high-pressure behavior of carbonates

“…A similar structural feature is also known for phosphates and sulfates. [30][31][32] Among these, the modification Pb 2 [C 2 O 6 ]-P% 3m1 shares the closest structural relationship with potassium dithionate, K 2 [S 2 O 6 ]-P321. 31 The structure of K 2 [S 2 O 6 ]-P321 can also be represented as a deformed two-layer close packing (hcp) of cation atoms.…”