报道了氰尿酸钡［Ｂａ（Ｃ_３Ｈ_２Ｎ_３Ｏ_３）_２·（Ｈ_２Ｏ）_２］的晶体结构。晶体属三斜晶系，空间群为Ｐ１，晶胞参数为：ａ＝８．８８４（３）．ｂ＝９．４２２（４），ｃ＝７．２０１（４）Ａ，α＝９７．７５（４），β＝１０１．７６（４），γ＝８５．０５（３）°；Ｍ_ｒ＝４２９．４９，Ｚ＝２，Ｄ_ｃ＝２．４４ｇ／ｃｍ~３。Ｖ＝５８３．６（４）Ａ~３，μ＝３４．５６ｃｍ~（－１），λ（ＭｏＫα）＝０．７１０６９Ａ，Ｆ（０００）＝４１２，Ｉ＞３σ（Ｉ）的衍射点２０９１个。结构用ＴＥＸＳＡＮ程序包以直接法解出，经全距阵最小二乘法修正，最后Ｒ因子为０．０２９，Ｒ_ω＝０．０３７．中心离子Ｂａ~（２＋）的配位数为１０，Ｂａ~（２＋）离子处于６个配位原子形成的平面的中心位置上，另外４个配位原子则处于平面外，分布在Ｂａ~（２＋）离子的周围。 The crystal structure of Ba (C_3H_2N_3O_3) _2 · (H_2O) _2] has been reported. The crystal belongs to the triclinic system, the space group is P1, the unit cell parameters are as follows: a = 8.884 (3). a = 97.75 (4), β = 101.76 (4), γ = 85.05 (3) °; M_r = 429 .49, Z = 2, D_c = 2.44g / cm ~ 3. 2091 diffraction spots of V = 583.6 (4) A~3, μ = 34.56cm -1, λ (MoKα) = 0.71069A, F (000) = 412 and I> 3σ (I) . The structure was solved directly by TEXSAN package and corrected by full-distance least square method. The final R factor was 0.029 and R_ω = 0.037. The coordination number of the Ba ~ (2+) ion in the center is 10, the Ba ~ (2+) ion is in the center of the plane formed by 6 coordination atoms, and the other four are outside the plane, 2+) ions around.