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A chirally helical coordination polymer,5-dicarboxylic acid) constructed from a Ni 4 L 4 building block exhibits spontaneous chiral resolution and the enantiomers of 1M and 1P have been confirmed by singlecrystal analysis and solid-state circular dichroism spectra. The magnetic properties of compound 1 are also discussed.

An enantioenriched three-dimensional quartz-type framework {[Ni(1.5)(tzdc)(H(2)O)(3)]·3H(2)O}(n) (H(3)tzdc = 4H-1,2,4-triazole-3,5-dicarboxylic acid) possessing chiral channels is obtained through spontaneous asymmetric crystallization without any enantiopure additive.

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Simulated seawater (SW) was used to fabricate magnesium oxychloride cement (MOC) pastes. Compressive strength, water resistance, performance under salt attack, thermal stability, mineral composition and microstructure were studied in detail by using a materials testing system, thermogravimetry and differential scanning calorimetry methods, X-ray diffraction and scanning electron microscopy. The results showed that the compressive strength, strength retention in distilled water and thermal stability of MOC pastes made with simulated SW were slightly lower than those of the control MOC pastes. The main hydration product of both the MOC pastes was 5Mg(OH)2.MgCl2.8H2O. The strength retention of the simulated SW MOC pastes was 11·27% higher than that of the fresh water (FW) MOC pastes after 28 d of immersion in raw brine. The properties of the MOC pastes appeared to be unchanged when manufactured using simulated SW instead of FW. Due to its good performance under salt attack, the MOC pastes mixed with simulated SW show potential as salt pan material.

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According to the C20 Portland cement concrete (PCC) batching standard, magnesium oxychloride cement concrete (MOCC) is made using bischofite from salt lakes and light-burned magnesium oxide as the main raw materials. In this work, the mechanical properties of MOCC (setting time and compressive and flexural strengths) were tested. The rules governing the phase composition and microstructure changes of the hydration products were analysed using X-ray diffraction and scanning electron microscopy. The results showed that MOCC solidifies rapidly, has high early compressive and flexural strengths and exhibits excellent long-term mechanical properties, far superior to those of the same grade of C20 PCC. The main phase at different curing times was found to be 5Mg(OH)2.MgCl2.8H2O (5.1.8). With hydration from 7 to 365 d, the amount of 5.1.8 fluctuated between 30% and 37% and the microscopic crystal morphology of the MOCC changed significantly. Importantly, fibre-like and rod-like crystals were observed to transform into their respective gel phases from 180 to 270 d. This phenomenon explains the fact that the content of 5.1.8 was the lowest but the mechanical strength of MOCC was the highest at 180 and 270 d. It was also confirmed that 5.1.8 gel is one of the main strength phases.

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