Ti-2(Ti0.16Ni0.43Al0.41)(3) is a novel compound (labeled as tau(6)) in the Ti-rich region of the Ti-Ni-Al system in a limited temperature range 870 < T < 980 degrees C. The structure of tau(6)-Ti-2(Ti,Ni,Al)(3) was solved from a combined analysis of X-ray single crystal and neutron powder diffracton data (space group C2/m, a = 1.85383(7) nm, b = 0.49970(2) nm, c = 0.81511(3) nm, and beta = 99.597(3)). tau(6)-Ti-2(Ti,Ni,Al)(3) as a variant of the V-2(Co0.57Si0.43)(3)-type is a combination of slabs of the MgZn2-Laves type and slabs of the Zr4Al3-type forming a tetrahedrally close-packed Frank Kasper structure with pentagon triangle main layers. Titanium atoms occupy the vanadium sites, but Ti/Ni/Al atoms randomly share the (Co/Si) sites of V-2(Co0.57Si0.43)(3). Although tau(6) shows a random replacement on 6 of the 11 atom sites, it has no significant homogeneity range (similar to 1 at. %). The composition of tau(6) changes slightly with temperature. DSC/DTA runs (1 K/min) were not sufficient to define proper reaction temperatures due to slow reaction kinetics. Therefore, phase equilibria related to tau(6) were derived from X-ray powder diffraction in combination with EPMA on alloys, which were annealed at carefully set temperatures and quenched. tau(6) forms from a peritectoid reaction eta-(Ti,Al)(2)Ni + tau(3) + alpha(2) <-> tau(6) at 980 degrees C and decomposes in a eutectoid reaction tau(6) <-> eta + tau(4) + alpha(2) at 870 degrees C. Both reactions involve the eta-(Ti,Al)(2)Ni phase, for which the atom distribution was derived from X-ray single crystal intensity data, revealing Ti/Al randomly sharing the 48f- and 16c-positions in space group Fd (3) over barm (Ti2Ni-type, a = 1.12543(3) nm). There was no residual electron density at the octahedral centers of the crystal structure ruling out impurity stabilization. Phase equilibria involving the tau(6) phase have been established for various temperatures (T = 865, 900, 925, 950, 975 degrees C, and subsolidus). The reaction isotherms concerning the tau(6) phase have been established and are summarized in a Schultz-Scheil diagram.