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Single CdPS3 crystals were studied at room temperature by x-ray photoemission spectroscopy and x-ray induced Auger spectroscopy. A single-peak structure was seen for all the core levels studied. Also, Cd 4d levels were discrete and well localized, in good agreement with the transition-metal weakly interacting model according to which the transition metal-sulfur bond is weak. Further data regarding the characteristics of the cadmium-sulfur bond in CdPS3 were obtained from the computed modified Auger parameter for Cd.

A study was conducted on the room temperature absorption and reflectivity of layered Cd2P2S6 and Cd2P2Se6 crystals in the 1.6 eV to 5.5 eV photon energy range. The compounds exhibited associated photon energies of 74 meV and 50 meV, respectively. The transition metal weakly interacting model was adopted to represent the similarities between the reflectivity spectra of both compounds.

Sodium intercalated manganese thiophosphate [Na.sub.0.62][Mn.sub.0.69]P[S.sub.3] powders are prepared by a two-step ion-exchange process and dielectric measurements are performed as a function of both temperature and frequency by using the autobalancing bridge method. The nature of these hopping charge carriers is formulated based on the ion-exchange intercalation process and the comparison with the dielectric spectra.

The synthesis and spectroscopic properties of polycrystalline powders of [Na.sub.2x][Mn.sub.1-x]P[S.sub.3] obtained from layered MnP[S.sub.3] material by successive ion-exchange intercalation of potassium and sodium ions are described. The results have verified the presence of [Na.sup.+] in [Na.sub.0.62][Mn.sub.0.69]P[S.sub.3] and their weak link that allow exchange with other guest species.

The [Cs.sub.2x][Mn.sub.1-x]P[S.sub.3] compound is prepared by the cesium ion-exchange intercalation reaction on MnP[S.sub.3] and is characterized by various spectroscopic methods. The studies have shown that the [Cs.sup.+] intercalation process in MnP[S.sub.3] is complete and has led to the creation of intercalated vacancies.

Lithium intercalate thin films was obtained from MnPS(sub 3) starting material and characterized by the x-ray photoelectron spectroscopy technique and the regions of Mn 2p and 3p, P and S 2p, and Li 1s core levels was investigated. The analysis of the spectra has revealed the lack of nonequivalent atoms of Mn, P, S, and Li and the presence of shake-up-type satellites at the Mn 2p and 3p core levels suggest that Li (sub 2xMn(sub 1-x)PS(sub 3) is a large gap insulating Mn compound analogously to the parent MnPS(sub 3).

Electrical properties of single crystals of the MnPSe3, CdPSe3, and CdPS3 layered compounds are investigated by in-layer dc conductivity and photoconductivity measurements as a function of temperature. At high temperatures, the dc conductivity of all three compounds shows an Arrhenius temperature dependence while photoconductivity is thermally activated only for MnPSe3 and almost temperature independent for CdPSe3 and CdPS3.