Sodium chromate(II) at 296 K (neutron)

Structure and vibrational dynamics of sodium sulfate/sodium chromate solid solutions

“…Sodium chromate, Na 2 CrO 4 is described at room temperature by phase II which is isomorphous with sodium sulfate ͑III͒. 3, 6 This phase is stable until 427°C, where a reversible transition into phase I occurs. 7 Other II→I transition temperatures from 413°C to 427°C have been reported.…”

Pressure–induced phase transitions of Zn₂SiO₄ III and IV studied using in–situ Raman spectroscopy

“…Therefore, possible candidates for the highpressure phases can be narrowed down to olivine (space group: Pnma), thenardite (Fddd), Na 2 CrO 4 (Cmcm), and Ag 2 CrO 4 (Pnma). Among them, the thenardite structure has a tetrahedral Zn site (Hawthorne and Ferguson, 1975), whereas the Na 2 CrO 4 and Ag 2 CrO 4 structures have both tetrahedral and octahedral Zn sites (Nimmo, 1981;Jacobson and Hackert, 1971). Therefore, thenardite is a less likely candidate as a high-pressure phase.…”

Structural chemistry of A 2 MX 4 compounds (X = O, F) with isolated tetrahedral anions: search for the densest structure types

“…A plot of reduced cell parameters for A 2 MnO 4 versus octahedral A + radii: 1, Na 2 MnO 4 (Kopelev et al, 1991); 2, Ag 2 MnO 4 (Ag 2 CrO 4 type; Chang & Jansen, 1983); 3, -K 2 SO 4 type for A = K, Rb, Cs (Kopelev et al, 1991;Palenik, 1967;Fischer & Hoppe, 1995). Plots of reduced cell parameters for A 2 BeF 4 (1-4) and A 2 CrO 4 (5-10) versus octahedral A + radii: 1 and 5, phenacite type for A = Li (Hartman, 1989;Brown & Faggiani, 1975); 2, olivine-type LiNaBeF 4 (Jahn, 1954) and Na 2 BeF 4 (Deganello, 1972); 3 and 7, glaserite-type NaKBeF 4 , NaTlBeF 4 and Na 1/2 Rb 3/2 BeF 4 (Pontonnier et al, 1972), Na 1.6 K 0.4 CrO 4 (PDF 26-1332, Goldberg et al, 1973), Na 3/2 K 1/2 CrO 4 (PDF 26-1467; Goldberg et al, 1973), NaKCrO 4 (PDF 26-1468; Goldberg et al, 1973), K 3/2 Na 1/2 CrO 4 (Madariaga & Breczewski, 1990); 4 and 9, -K 2 SO 4 type for A = K, Tl, Rb, Cs (McGinnety, 1972;da Silva et al, 2005a,b;Carter & Margulis, 1972;Aleksovska et al, 1998;ICSD 300021;Morris et al, 1981); 6, Na 2 CrO 4 (Nimmo, 1981); 8, Ag 2 CrO 4 (Hackert & Jacobson, 1971); 10, Tl 2 CrO 4 (Fá bry et al, 2010). solutions which enable extending the stability ranges of structures in terms of radii.…”

“…Another contradiction with the classical principles is the fact that conventional CNs (shown in Fig. 11 First and second coordination spheres of M atoms in A 2 MO 4 : (a) Li 2 SO 4 (Nord, 1976); (b) phenacite-type Li 2 BeF 4 (Collins et al, 1983); (c) olivine Mg 2 SiO 4 (Yamazaki & Toraya, 1999); (d) Na 2 MnO 4 (-K 2 SO 4 type; Kopelev et al, 1991); (e) and (f) Ge1 and Ge2 in Sr 2 GeO 4 (Nishi & Takeuchi, 1996); (g) glaserite K 3 Na(SO 4 ) 2 (Okada & Ossaka, 1980); (h) thenardite Na 2 SO 4 (Nord, 1973); (i) Na 2 CrO 4 (Nimmo, 1981); (j) Ag 2 CrO 4 (Hackert & Jacobson, 1971); (k) -K 2 SO 4 (McGinnety, 1972); (l) K 2 MoO 4 (Gatehouse & Leverett, 1969); (m) larnite -Ca 2 SiO 4 (Jost et al, 1977); (n) and (o) Cr1a and Cr1b in Tl 2 CrO 4 (Fá bry et al, 2010); (p) spinel-type Co 2 GeO 4 (Furuhashi et al, 1973).…”