Composite borate-phosphate compounds have always attracted much attention for their structure diversity and interesting properties.In this work,a new borate-phosphate Cs Na_(2)Lu_(2)(BO_(3))(PO_(4))_(2) (CNLBP) was found for the first time and its structure was characterized by single-crystal X-ray diffraction method.It crystallizes in orthorhombic system,space group Cmcm with a=6.8750(5),b=14.6919(1),c=10.5581(7)?,V=1066.44(1)?^(3),Z=4,M_(r)=777.58,D_(c)=4.843 g/cm^(3),F(000)=1368,μ(Mo Kα)=22.20 mm^(-1),R(F^(2)>2σ(F^(2)))=0.0173 and w R(F^(2))=0.0367.The structure of CNLBP features a chain framework of[Lu_(2)(BO_(3))(PO_(4))_(2)]_(∞)that delimits 1Dtunnels filled by Na^(+)and Cs^(+)ions.Phosphors CNLBP:x Tb (x=0,0.1,0.2,0.4,0.6,0.8,1.0) were prepared,and it can emit bright green light under near-UV excitation due to the ^(5)D_(4)→^(7)F_(j) (j=6,5,4,3) transition of Tb^(3+).Due to the large separation of Lu^(3+)ions in CNLBP structure lattice,the optimal concentration of Tb^(3+)is 80%,and concentration quenching occurs only for the full Tb^(3+)concentration.
Langbeinite type compounds are a large kind of oxometallate with good flexibility structure.Herein,we synthesized a new langbeinite type compound K_(2)Dy_(1.5)Ta_(0.5)(PO_(4))_(3),in which the Dy^(3+)and Ta^(5+)were blended to occupy the same crystallographic sites.Simultaneously,solid solutions of K_(2)Dy_(1.5-x)Eu_(x)Ta_(0.5)(PO_(4))_(3)(x=0-1.5)were prepared and their photoluminescence properties were investigated.Due to energy transfer from Dy3+to Eu3+,both Dy3+and Eu3+characteristic emissions are observed under 393 nm light excitation.The emitting color of K_(2)Dy_(1.5-x)Eu_(x)Ta_(0.5)(PO_(4))_(3)turns from green through yellow to red by simply adjusting the Eu^(3+)concentration from 0 to 0.4.Moreover,K_(2)Dy_(1.48)Eu_(0.02)Ta_(0.5)(PO_(4))_(3)phosphor possesses excellent fluorescence thermal stability and exhibits zero thermal quenching at 150℃.These results manifest that K_(2)Dy_(1.5-x)Eu_(x)Ta_(0.5)(PO_(4))_(3)solutions are promising multi-color emitting phosphors candidate for near-UV LED.
A new borate K3Pr3（BO3）4 has been prepared using a high temperature flux method and structurally characterized by single-crystal X-ray diffraction analyses.It crystallizes in triclinic system,space group ■ with a=9.0814（10）,b=10.8052（12）,c=14.0885（16）?,α=69.800（1）°,β=89.922（1）o,γ=89.892（1）°,V=1297.4（3）?3,Z=4,Mr=775.27,Dc=3.969 g/cm3,F（000）=1400,μ（MoKα）=12.11 mm-1,R（F2>2σ（F2））=0.028 and wR（F2）=0.054.Interestingly,the crystal of K3Pr3（BO3）4 was twinned by pseudo-merohedry that is mimic monoclinic space group P2/c.The structure of K3Pr3（BO3）4 exhibits a three-dimensional（3D）network based on isolated anionic（BO3）3- units that are further bridged by K+and Pr3+ions.Furthermore,X-ray diffraction（XRD）,IRspectrum and photoluminescence（PL）properties were studied.
SHI Jian-ChaoZHAO DanXUE Ya-LiZHANG Shi-RuiLI Fei-Fei
