Ion-exchange synthesis and superconductivity at 8.6 K of Na2Cr3As3 with quasi-one-dimensional crystal structure

A new Cr-based quasi-one-dimensional superconductor Na2Cr3As3 was synthesized by an ion-exchange method in sodium naphthalenide solution. The crystals are thread-like and the structure was analyzed by X-ray diffraction with a noncentrosymmetric hexagonal space group P-6m2 (No. 187), in which the (Cr3As3)2- linear chains are separated by Na+ ions, and the refined lattice parameters are a = 9.239(2) {\AA} and c = 4.209(6) {\AA}. The measurements for electrical resistivity, magnetic susceptibility, and heat capacity reveal a superconducting transition with unconventional characteristic at the Tc of 8.6 K, which exceeds that of all previously reported Cr-based superconductors

Selling Price and Marketing Time in the Residential Real Estate Market

This paper examines the complex relationship between selling price, listing price, housing features, housing market conditions, and marketing time in a large sample of single-family homes. A key finding is that, for houses of equal quality, marketing time varies with the level of contract mortgage rates. Overpricing by sellers is not a successful strategy, however, even under market conditions in which houses in general sell relatively quickly. Finally, marketing time is significantly shorter for newer homes, particularly those in medium or high price ranges, but a home's size has no significant effect on the number of days it remains on the market.