Synthesis and Structure Determination of the Quaternary Zinc Nitride Halides Zn2NX1−yX′y (X, X′ = Cl, Br, I; 0 < y < 1)
The quaternary series Zn2NCl1−yBry and Zn2NBr1−yIy were synthesized from solid-liquid reactions between zinc nitride and the respective zinc halides in closed ampoules, and the evolution of their crystal structures was investigated by single-crystal and powder X-ray diffraction. Zn2NX1−yX′y (X, X′ = Cl, Br, I) adopts the anti-β-NaFeO2 motif in which each nitride ion is tetrahedrally coordinated by four zinc cations, and the halide anions are located in the voids of the skeleton formed by corner-sharing [NZn4] tetrahedra. While Zn2NCl1−yBry crystallizes in the acentric orthorhombic space group Pna21 (No. 33), isotypic to Zn2NX (X = Cl, Br), the structure of Zn2NBr1−yIy is a function of the iodide concentration, namely, Zn2NBr (Pna21) for low iodine content and Zn2NI (Pnma) for higher (y ≥ 0.38).
A new yttrium sesquichloride nitride, .beta.-Y2Cl3N, that is isostructural with the binary yttrium sesquichloride
Reactions of YCl{sub 3}, YN, and Y metal in sealed Nb containers over a range of temperatures and compositions afford {beta}-Y{sub 2}Co{sub 3}N, whereas only {alpha}-Y{sub 2}Cl{sub 3}N in the ({alpha}-)Gd{sub 2}Cl{sub 3}N structure is obtained in the absence of metal. {beta}-Gd{sub 2}Cl{sub 3}N is synthesized similarly. The {beta}-Y{sub 2}Cl{sub 3}N ({beta}-Gd{sub 2}Cl{sub 3}N) gives a powder pattern that is indistinguishable from that of the infinite cluster chain phase Y{sub 2}Cl{sub 3} (Gd{sub 2}Cl{sub 3}) except from small increases in lattice parameters corresponding to a 2% (1%) increase in cell volume. Crystal structures of both the {alpha}- and {beta}- compounds are reported. A single-crystal x-ray study of {beta}-Y{sub 2}Cl{sub 3}N (R = 3.9%, R{sub w} = 4.8%) demonstrates that the nitrogen atoms are positioned in tetrahedral metal sites above and below the shared metal edges of the infinite chain of octahedra found in Y{sub 2}Cl{sub 3}. The need for metal in the syntheses, the black color of the fibrous crystals, and the refined occupancy of nitrogen (81 (2)%) in the yttrium phase all suggest a small nitrogen deficiency in {beta}-(Y,Gd){sub 2}Cl{sub 3}N. The close correspondence of distances in the binary vs the ternary ({beta}) sesquichlorides, particularly the small (0.024 {angstrom})more » increase in the shared Y-Y edge, is discussed. 22 refs., 1 fig., 3 tabs.« less
Introduction and experience with the primary mail services based on their names for students
Kyushu University provided mail service based on student IDs such as "1AB10123X" to the university students for many years. Using this model, we had problems communicating with the students who graduated from the University and enrolled in the graduate school. The students received new mail addresses based on their new student IDs such as "2AB12789Y". Faculty members were forced to change the student mail addresses in the mailing lists and in their mail client address book. Furthermore, students were forced to notify the e-mail address change to all of their existing contacts. We introduced a new mail system to provide addresses based on the student name, as well as student ID in April 2011. The new naming convention uses the following format: lastname.firstname.999 where 999 is a random number of 3 digits. Students can select some combination patterns of their first and last names for Japanese. We also consider the middle names for foreign students. In the system implementation, we did not have the formal information of alphabetical names for students. We generated alphabetical names from Japanese Katakana names. It is not easy for us to get the appropriate name in this manner. We implemented a confirmation stage of the alphabetical name at first use, and then students can select their mail addresses for their convenience. We paid much attention to the user interface in the system. Since April 2011, the number of users who use the mail address based on their own name has been increasing gradually. This paper will detail the usage status of the new system.